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EXTRACTED FROM SEI HON ONE 01 rHE FISHERIES U*D FISHERY I MDCSTRIES " 
I 111. 1 KITED STA'J 1> P 



NATURAL HISTORY OF ECONOMIC MOLLUSKS 



UNITED STATES. 



ERNEST INGEKSOLL and JOHN A. RYDER 



WASHINGTON : 

GOVERNMENT PRINTING OFFICE. 

1893. 



> / 

JO/ V, 



By tranrf!?? 1 
AUG -1 190c 



CUTTLES, SNAILS, BIVALVES, ETO. 



By Ernest Engersoll. 



205. THE CUTTLES— CEPHALOPODA. 

The mollusks called "Cuttles" or "Cuttle-fishes" bear a very important relation to the fisheries 
and consequently to the food supply of the United States. It has recently been ascertained that 
some of these Cuttlefishes attain huge bulk and corresponding abilities for destruction. The two 
species of Architeuthis (A. princeps and A. Harveyi), roaming through the North Atlantic and now 
ami then stranded upon the beaches of Newfoundland, have each a total length of from thirty to 
fifty feet, and a weight of solid flesh amounting to thousands of pounds. 

" The Cuttles," says Dr. Philip Carpenter, " have very acute senses. They have an approach 
to a brain, inclosed in a cartilaginous skull. They can hear sounds, and evidently enjoy the taste 
of their food. They have a large, fleshy tongue, armed with recurved prickles, like that of the lion. 
They either crawl on their head tail upwards, or swim, tail foremost, by striking with their arms, 
or squirt themselves backwards by forcing water forward through their breathing funnels. 

" They are ferocious creatures, the tyrants of the lower orders, and do not scruple to attack 
and devour even fishes. The larger kinds are deservedly dreaded by man. Their weapons con- 
sist in their powerful arms, which are abundantly furnished with rows of cup-like suckers, each 
of which fastens on its prey or its foe like a limpet to the rock. Often these are accompanied with 
sharp-curved teeth, strong enough to be preserved even in fossil species." 

The giant Cuttle-fishes of the north (Architeuthis) and the commoner Squids and Calamaries of 
our Atlantic coast belong to the ten-armed division of the order termed Decapods. The three 
smaller species ordinarily met with are Loligo Pealei, Loligo Pealei var. pallida, and Ommastrephes 
illecebrosus. On the extreme southern coast they are replaced by an Octopod (Octopus granulatus). 

Of these four, Loligo Pealei is the common Squid of Long Islaud Sound and southward, and 
when full grown it is more than a foot in length. The color when living is very changeable, owing 
to the alternate contractions of the color-vesicles or spots, but red and brown predominate, so as 
to give a general purplish-brown color. An allied variety or subspecies, named pallida, is a 
"pale, translucent, gelatinous-looking" creature, with few spots on the back and nearly white 
beneath. Commonly five or six inches long, exclusive of the arms, it frequently grows much larger, 
and is of broader and stouter proportions than the type-form, from which it is further distin- 
guished by its broader caudal fin and the larger size of its suckers. It belongs especially to the 
western end of Long Island Sound, " where it is abundant with the schools of menhaden, on which 
it feeds." 

"This species," writes Verrill, 1 "is found along the whole coast from South Carolina to Massa- 
chusetts Bay. 

" It is the Common Squid from Cape Hatteras to Cape Cod. In Long Island Sound and Vineyard 
Sound it is very abundant, and is taken in large numbers in the fish-pounds and seines, and used 
to a large extent for bait. It is comparatively scarce, though not rare, north of Cape Cod. The 
young were trawled by us in many localities in Massachusetts Bay in 1878. Large specimens were 
taken in the pounds at Provincetown, Massachusetts, August, 1879. It was taken in considerable 
1 Report U. S. Fish Commission, part vii, 1882, p. 355. 



688 NATUEAL HISTOEY OF AQUATIC ANIMALS. 

quantities, in breeding condition, in the fish-pounds at Cape Ann, near Gloucester, Massachusetts, 
May, 1880 (var. borealis). It has not been observed north of Cape Aun. Its southern limit is not 
known to me, but it appears to have beeu found on the coast of South Carolina. 

"In depth, it has occurred from low-water mark to fifty fathoms. The eggs 1 have often been 
taken by us in the trawl, in great abundance, at many localities along the southern shores of New 
England, in five to twenty-five fathoms. 

"It is known to be a very important element in the food supply of the bluefish, tautog, sea- 
bass, striped bass, weakfish, king-fish, and many other of our larger market fishes. 

"In the Gulf of Mexico this species appears to be replaced by another species {Loligo Gahi 
D'Orbigny). Of this we have several specimens, collected on the west coast of Florida, at Egmont 
Key, near Tampa Bay, by Col. B. Jewett and Mr. W. T. Coons. This species is closely allied to 
L. Pealei, but has a more slender form, with the caudal fin shorter and narrower in proportion to 
the length of the mantle. The pen has a shorter and broader shaft, and a narrower and more 
oblong blade, which has parallel, thickened, and darker-colored portions between the midrib and 
margins. The tentacular suckers have their horny rings more coarsely and equally toothed, there 
being only a partial alternatiou of larger and smaller teeth. 

"Along our southern coast, from Delaware Bay to Florida, a much shorter and relatively 
stouter species (Loligo brevis Blaiuv.) occurs, which might be mistaken by a careless observer for 
the present species. In addition to its shorter body, it has very different large, tentacular suckers, 
with the teeth on the horny rim coarser and all of similar form and size. Its pen is also shorter 
and relatively broader, and different in structure." 

"I am not aware," he says elsewhere, 2 "that any definite information has hitherto been 
published as to the rate of growth or length of life of any of our cephalopods. By some writers it 
has beeu stated that the Squids are all annual, but this seems to be a mere assumption, without 
any evidence fm its basis. Therefore I have for several years past preserved large numbers of 
specimens of the young of Loligo Pealei, collected at different seasons and localities, in order to 
ascertain, if possible, the rate of growth and the size acquired during the first season, at least. 
One of the following tables (I) shows some of the data thus obtained. 3 

"There is considerable difficulty in ascertaining the age of these Squids, owing to the fact that 
the spawning season extends through the whole summer, so that the young ones hatched early in 
June are as large by September as those that hatch in September are in the following spring. 
Owing to the same cause, most of the large lots of young Squids taken in midsummer iuclude 
various sizes, from those just hatched up to those that are two or three inches long. They are 
often mixed with some of those of the previous year, considerably larger than the rest. Earlier in 
the season (in May and the first part of June), before the first-laid eggs begin to hatch, the 
youngest specimens taken (60 mm to 100 mm long) are presumed to belong to the later broods of 
the previous autumn, while those somewhat larger are believed to be from earlier broods of the 
previous summer, and to represent the growth of one year very nearly. 

"Taking these principles as a guide, I have arrived at the following conclusions from the data 
collected : 

"1. The young Squids begin to hatch at least as early as the second week in June, on the 

'In early summer this Squid resorts to gravelly and weedy bottoms to lay its eggs. They are contained in bunches 
or clusters, sometimes six or eight inches in diameter, consisting of hundreds of gelatinous capsufes each holding 
numerous eggs. These clusters arc attached to some lixed object, and the oysters upon planted beds offer conveniences 
which the Squid is very likely to adopt. This occurrence seems to be a source of decided harm in Delaware Bay, liir the 
oystermen there assert that the larger "'sea-grapes " (as they call the egg-bunches) lift many oysters from the bottom by 
their buoyancy and float them off iu stormy weather.— E. I. 

- Report U. S. Fish Commission, part vii, 1882, pp. 353-355. 

3 See the original article. 



BATE OF GEOWTB OF ZOUNG SQUIDS. 689 

southern coast of New England, and continue to batch till the middle of September, and perhaps 

later. 

"2. By the second week in July, the first hatched of the June Squids have grown to the size 
in which the body (or mantle) is 30""" to is-"" 1 Long; but these arc associated with others that are 
younger, of all sizes down to those just hatched. They begin to show a disposition to go in 
'schools' composed of individuals of somewhat similar sizes. 

"3. By the second week in August, the largest June Squids have become 50" ira to 6S n,m in 
length of body, and the later broods are 5 ,m " to 30""" long. As before, with these sizes occur others 
of all ages down to those just hatched. It should be observed, however, that in those of our 
tabulated lots taken by the trawl the very small sizes are absent, because they pass freely through 
the coarse meshes of the net. 

"4. By the second week in September, the June Squids have the mantle 60 mm to 82 mi " long. 
All the grades of smaller ones still abound. A few larger specimens, taken the last of August 
and in September, S4 mm to HO" 1 ™ long, may belong to the June brood, but they may belong to 
those of the previous autumn. 

"5. In the first week of November, the larger young Squids taken had acquired a mantle- 
length of 79™" to S5 mm , but these are probably not the largest that might be found. Younger 
ones, probably hatched in September and October, 8 mm to 20 mm in length of body, occurred in vast 
numbers November 1, 1874. The specimens taken November 16, off Chesapeake Bay, having the 
mantle 40 mm to 70™ m long, probably belong to the schools hatched in the previous summer. 

"0. In May and June the smallest Squids taken, and believed to be those hatched in the 
previous September or October, have the mantle 62 mm to 100 mm long. With these there are others 
of larger sizes, up to 152 mm to 188 mm , and connected with the smaller ones by intermediate sizes. 
All these are bebeved to belong to the various broods of the previous season. In these the sexual 
organs begin to increase in size and the external sexual characters begin to appear. The males 
are of somewhat greater length than the females of the same age. 

" 7. In July, mingled with the young of the season, in some lots, but more often in separate 
schools, we take young Squids having the mantle 75 mm to 100 mm long. These we can connect by 
intermediate sizes with those of the previous year taken in June. I regard these as somewhat 
less than a year old. 

"8. Beyond the first year it becomes very difficult to determine the age with certainty, for those 
of the first season begin, even in the autumn, to overlap in their sizes those of the previous year. 

"9. It is probable that those specimens which are taken in large quantities, while in breeding 
condition, during the latter part of May and in June, having the mantle 175 mm to 225 mm long in 
the females and 200 mm to 275 mm long in the males, are two years old. 

"10. It is probable that the largest individuals taken, with the mantle 300 mm to 425 mm long, 
are at least three years, and perhaps in some cases four years old. The very large specimens 
generally occur only in small schools and are mostly males. The females that occur with these 
very large males are often of much smaller size, and may be a year younger than their mates. 

" 11. When Squids of very different sizes occur together in a school, it generally happens 
that the larger ones are engaged in devouring the smaller ones, as the contents of their stomachs 
clearly show. Therefore, it is probable that those of a similar age keep together in schools for 
mutual safety. 

"12. Among the adult specimens of var. pallida taken November 16 and December 7, at 
Astoria, there are several young ones, from 75 nun to 120 mm in length, with rudimentary repro- 
ductive organs. These may, perhaps, be the young of the year, hatched in June." 
44 F 



690 NATURAL HISTORY OF AQUATIC ANIMALS. 

Young Squids iu inconceivable numbers, and even the adults, are greedily devoured by 
bluefish, black bass, striped bass, weakfish, mackerel, cod, and many other marine animals. 
Thus they are really of great importance as food for our most valuable market fishes. 

North of Gape Cod the Squid is represented by the Sea-arrow or Flyiug Calamary, Omnia- 
strephes illecebrosus, sometimes called "short-finned" in contrast to the long "fins" characteristic 
of the Loligos, which they resemble in size and color. 

Professor Verrill has given the following graphic account of this species : 

"When living, this is a very beautiful creature, owing to the brilliancy of its eyes and its bright 
and quickly-changing colors. It is also very quick and graceful in its movements. This is the 
most common ' Squid' north of Cape Cod, and extends as far south as Newport, Rhode Island, and 
in deep water to the region off Cape Hatteras. It is very abundaut in Massachusetts Bay, the 
Bay of Fundy, and northward to Newfoundland. It is taken on the coast of Newfoundland in 
immense numbers, and used as bait for codfish. It occurs iu vast schools when it visits the coast, 
but whether it seeks those shores for the purpose of spawning or in search of food is not known. 
I have been unable to learn anything personally in regard to its breeding habits, nor have I been 
able to ascertain that any one has any information in regard either to the time, manner, or place 
of spawning. At Eastport, Maine, I have several times observed them in large numbers in mid- 
summer. But at that time they seemed to be wholly engaged in the pursuit of food, following 
the schools of herring, which were then iu pursuit of shrimp (Thysanopoda norvegica), which occur 
in the Bay of Fundy, at times, in great quantities, swimming at the surface. The stomachs of the 
Squids taken on these occasions were distended with fragments of Thysanopoda, or with the flesh 
of the herring, or with a mixture of the two, but their reproductive organs were not in an active 
condition. The same is true of all the specimens that I have taken at other localities m summer. 
From the fact that the oviducts are small and simple, and the nidamental glands little developed, 
I believe that it will eventually prove that this species discharges its eggs free in the ocean, and 
that they will be found floating at the surface, either singly or in gelatinous masses or bands, not 
having any complicated capsules to inclose them. Nothing is known as to the length of time 
required by this species to attain its full size. It probably lives several years. 

"This Squid is an exceedingly active creature, darting with great velocity backward, or in 
any other direction, by means of the reaction of the jet of water which is ejected with great rone 
from the siphon, and which may be directed forward or backward, or to the right or hit, bj 
bending the siphon. Even when confined in a limited space, as in a fish pond, it is not an easy 
matter to capture them with a dip-net, so quick will they dart away to the right and left. When 
darting rapidly the lobes of the caudal fin are closely wrapped around the body and the arms are 
held tightly together, forming an acute bundle in front, so that the animal, in this condition, is 
sharp at both ends, and passes through the water with the least possible resistance. Its caudal 
fin is used as an accessory organ of locomotion when it slowly swims about or balances itself for 
some time nearly in one position in the water. 

"The best observations of the modes of capturing its prey are by Messrs. S. I. Smith and Oscar 
Harger, who observed it at Provincetowu, Massachusetts, among the wharves, in large numbers, 
July 28, 1872, engaged iu capturing and devouring the young mackerel, which were swimming 
about in ' schools,' and at that time were about four or five inches long. In attacking the mackerel 
they would suddenly dart backward among the fish with the velocity of an arrow, and as suddenly 
turn obliquely to the right or left and seize a fish, which was almost instantly killed by a bite in 
the back of the neck with their sharp beaks. The bite was always made in the same place, cutting 
out a triangular piece of flesh, and was deep enough to penetrate to the spinal cord. The attacks 



HABITS OF THE SEA-AIUiOW. 691 

were uot always successful, and were sometimes repeated a dozen times before one of these active 
and wary fisbes could be caught. Sometimes, after making several unsuccessful attempts, one of 
the Squids would suddenly drop to the bottom, and, resting upon the sand, would change its color 
to that of the sand so perfectly as to be almost invisible. In this position it would wait until the 
fishes eame back, and when they were swimming close to or over the ambuscade, the Squid, by a 
sudden dart, would be pretty sure to secure a fish. Ordinarily, wheu swimming, they were thickly 
spotted with red and brown, but when darting amoug the mackerel they appeared translucent and 
pale. The mackerel, however, seemed to have learned that the shallow water was the safest for 
them, and would hug the shore as closely as possible, so that in pursuing them many of the Squids 
became stranded and perished by the hundreds, for when they once touch the shore they begin 
to pump water from their siphons with great energy, and this usually forces them farther and 
farther up the beach. At such times they often discharge their ink in large quantifies. The 
attacks on the young mackerel were observed mostly at or near high water, for at other times the 
mackerel were seldom seeu, though the Squids were seen swimming about at all hours, and these 
attacks were observed both in the day and evening. 

" It is probable, from various observatious, that this and other species of Squids are mainly 
nocturnal in their habits, or at least are much more active in the night than in the day. Those 
that are caught in the pounds and weirs mostly enter in the night, evidently while swimming 
along the shores in 'schools.' They often get aground on the sand-flats at Provincetown, 
Massachusetts, in the night. On the islands in the Bay of Fundy, even where there are no flats, 
I have often found them in the morning stranded on the beaches in immense numbers, especially 
when there is a full moon, and it is thought by many of the fishermen that this is because, like 
many other nocturnal animals, they have the habit of turning toward and gazing at a bright 
light, and since they swim backwards, they get ashore on the beaches opposite the position of the 
moon. This habit is also sometimes taken advantage of by the fishermen, who capture them for 
bait for codfish. They go out in dark nights with torches in their boats, and by advancing slowly 
toward a beach drive them ashore. They are taken in large quantities in nets and pounds, and 
also by means of 'jigs' or groups of hooks, which are moved up and down in the water, and to 
which the Squids cling, and are then quickly pulled out of the water. They are also sometimes 
caught by fish-hooks, or adhering to the bait used for fishes. 

"Their habit of discharging an inky fluid through the siphon, when irritated or alarmed, is 
well known. The ink is said to have caustic and irritating properties. 

" This Squid, like the Loligo, is eagerly pursued by the cod and many other voracious fishes, 
even when adult. Among its enemies while young are the full-grown mackerel, who thus retaliate 
for the massacre of their own young by the Squids. The specimens observed catching young 
mackerel were mostly eight to ten inches long, and some of them were still larger. 

" This species, like the common Loligo, has the instincts and habits of a cannibal, for small 
Squids of its own species form one of the most common articles of its diet. From an adult female 
of ordinary size (G, of our tables), caught at Eastport, Maine, I took a great mass of fragments 
of small Squids, with which the stomach was greatly distended. These fragments completely 
tilled a vial having a capacity of four fluid ounces. 

"From the rapidity with which the Squids devour the fish that they capture it is evident 
that the jaws are the principal organs used, and that the odontophore plays only a subordinate 
part iu feeding. This is confirmed by the condition of the food ordinarily found in the stomach, 
for both the fishes and the shrimp are usually in fragments and shreds of some size, and smaller 
creatures, like amphipods, are often found entire, or nearly so; even the vertebras and other 



692 NATURAL HISTORY OF AQUATIC ANIMALS. 

bones of herring are often present. On the other hand, in some specimens, the contents of the 
stomach are finely divided, as if the odontophore had been used for that purpose." 1 

The loss which the fisheries sustaiu through their voracity, however, is probably equalized by 
the food which Cuttlefishes furnish the carnivorous fishes and various other denizens of the deep. 
For example, the sperm whale seems to rely largely upon a diet of big Squids, sinking to the 
bottom where they are groping about, to drag them up, or nipping off their large arms as they 
swim about near the surface. Dolphins and porpoises also prey upon the Cuttles, and all the 
flesh-eating fishes pursue and devour them at every opportunity, particularly the cod and bluefish. 

Knowledge of this fact long ago led to the Squid being taken by fishermen as an attractive 
bait. More than half of all the Bank fishing is said to be with such bait. When the shoals of 
this mollusk \Loligo Squid] approach the coast hundreds of vessels are ready to capture them, 
forming an extensive cuttle fishery, engaging five hundred sail of French, English, and American 
ships. Their habit of moon-gazing, also, is sometimes taken advantage of on the coast of Maine 
by the fishermen, who capture them for bait for codfish ; they go out in dark nights with torches 
in their boats and by advancing slowly toward a beach drive them ashore. Violent storms heap 
great windrows of dead Squids on the beach, where they are gathered up, and they are also 
sometimes taken on lines adhering to the bait set for fishes. These '■ drives" and accidents 
happen in the spring, when Cuttles are flocking into shallow water to lay their eggs. 

Since this solidly-fleshed animal is so extensively eaten by other animals it is not surprising 
to find that men also should number it among the edible products of the sea. "The flesh of the 
large cephalopodous animals," says Simmonds, 2 " was esteemed as a delicacy by the ancients. 
Most of the Eastern nations, and those of the Polynesian Islands, partake of it and relish it as 
food. They are exposed for sale dried in the bazaars or markets throughout India, and . . . 
dried Cuttle-fish may be seen among the articles of Chinese, Japanese, and Siamese food. In 
Chili the flesh is also considered a delicacy, and in Barbados the bastard Cuttle-fish or 'Calmar' 
(Loligo sagittata Lam.) is used as an article of food by the lower classes." 

In the Mediterranean also, particularly near Tunis, and along the Portugal coast, the catch 
and consumption of Cuttles is large, amounting to nearly a million pounds a year, most of which 
is sold in Greece, after being salted and dried or pickled. These are Octopods. The same sort of 
Cuttle-fish {Octopus punctatus) serves the double purpose on the Pacific coast, from California to 
Alaska, of bait for the fisheries and food for the Indians. For the latter purpose it is chiefly 
sought in Puget Sound, where the coast tribes hunt and kill Octopods often large enough to be 
dangerous foes in a quarrel, by going to their haunts in canoes and spearing them. To some small 
tribes the Octopus affords the chief supply of animal food. There is no reason why squid-flesh 
from the northern Atlantic Ocean should not become available as food, and prove desirable — to 
those who like it. It would be both wholesome and cheap; and a single ArcMteuthis would 
furnish a meal for a frigate's crew. In Bermuda the Octopus granulatus regularly forms a portion 
of the fare of the fisher families. As the Bermudan fish and methods of capture prevail across 
among the Florida reefs, uo doubt this habit prevails there also. In New York City there is a 
considerable sale of fresh Squids to foreign residents, and the trade is increasing. There seems 
no reason why on some coasts this flesh should not be far more thoroughly utilized than it 
is at present. 

In addition to its value as a bait, or as a source of oil (our Ommastrephes has been thus 
utilized somewhat), and as possible food, the cephalopods contribute two or three useful articles 

1 Report U. S. Fisli Commission, part vii, 1882, pp. 305-308. 

2 Commercial Products of the Sea, p. 116. 



THE SEA-SNAILS. 693 

to commerce. A large portion of them carrj under the skin of the bach a long, flat, calcareous 
"bone" or plate, which serves as a stay or support to the frame in lieu of a skeleton. In some 

species it is long and slender like a quill-pen. This bone, reduced to powder, forms a useful 
pounce, "used in rewriting over erasures to prevent blotting, and in medicine as an antacid." li 
is also combined into a dentifrice. The principal use for it, nevertheless, is for feeding to caged 
birds requiring lime for their health. For this purpose several hundred-weight of " cuttle-bone " 
are brought into the United States annually. It is furnished chiefly from Chinese waters, 
but is also collected floating in the Mediterranean. None of our American species afford a useful 
cuttle-bone, however; so that this import can scarcely be diminished. The name "Calamary" 
is often applied to a Cuttle-fish, and arises from the fact that each of them carries in an internal 
gland a supply of blue-black, ink-like liquid, which upon the slightest alarm he discharges into 
the water, making a dense cloud under cover of which he rapidly retreats. 1 This ink, removed and 
dried into little cakes, with a greater or less adulteration, forms the sepia of painters and the 
India ink of draughtsmen. Now it is brought almost wholly from Oriental ports, via London, 
but it might probably be saved on our coast as well. Provided with pen and ink on all occa 
sions, these mollusks seem truly to stand at the head of the class of animals they represent — 
not wholly because of their superior size and loftier brain and organization, but also ou the score 
of literary accomplishments. 

206. THE SEA-SNAILS— GASTEROPODA. 

The Gasteropod mollusks, bearing a shell in a single piece and usually spiraJly whorled, are 
not of much direct utility to man, as a rule, on this side of the world, north of the tropics ; but there 
are a few species which deserve mention. Their principal claim to notice in 1 bis connection lies 
in the fact that they figure upon the habitual bill of fare of various fishes. No doubt the list 
appended might be greatly enlarged if we were better informed, particularly in respect to the 
southern coast. Thus far the chief knowledge possessed in respect to the molluscan food of 
American fishes is derived from Gould's " Report upon the Invertebrates of Massachusetts," and 
Prof. A. E. Verrill's report to the United States Fish Commission. From this and other sources 
is compiled the succeeding catalogue of species of Gasteropod mollusks that are fed upon by 
fishes; these, it must be observed, are confined to the Atlantic coast, and, to a great extent, to the 
waters of New England, through lack of information in respect to the similar food of the fishes of 
the southern and the western coast. The list includes about fifty species, and reads : 

Bela turricula, Bela harpularia, Bela pyramidalis, Bela decussata, Admete Gouthouye, Neptunea 
despecta, Buccinum undatum, Buccinum ciliatum, Tritia trivittata, llyanassa obsoleta, Trophon 
clathratus, Trophon clathratus var. scalar if or mis, Purpura lapillus, Astyris rosacea, Astyris lunata. 
N~atica clausa, Lunatia. heros, Lunatia grcenlandica, Lunatia immaculata, Amauropsis islandica, 
Velutina sonata, Velutina laevigata, Lamellaria perspicua, Littorina — several species, Triforis nigro- 
ductus, Bittium nigrum, Turritella erosa, Trichotropis borealis, Grepidula fornicata, Grepidula plana, 
Aporrhais occidentalis, Scalar ia grcenlandica, Scalaria Novanglia, Margarita cinerca, Margarita 
grcenlandica, Margarita argentata, Machmroplax obscura, Puncturella noachina, Tonicella marmora, 
Trachydermon albus, Trachydermon ruber, Chiton — various species, Auricula vestita var. Emersonii, 

1 There are frightful tales abroad of the ferocity with which the larger of these creatures will attack man, and they 
are greatly dreaded by the shell-divers of the South Seas; but the truth is the Cuttle-fish is timid, and mil hide or run 
away whenever he can from anything so large and strange as a man ; that is, any Cuttles smaller than the giants of 
Newfoundland. A diver who touched a large Octopus would instinctively be seized, of course, since the creature would 
know no different course of action; but voluntary attack is not credited by those who know most about the habits of the 
animal. 



694 NATURAL HISTORY OF AQUATIC ANIMALS. 

Odostomia striatula, Philine lineolata, Amphisphyra Memalis, Amphisphyra debilis, Diaphana Gouldii, 
and Gylichna alba among salt-water forms; with many species of Meiampus, Paludina, Planorbis, 
Limnea, Physa, and other fresh- water genera. 

But many of these species, and several not mentioned here, have additional claims to our 
notice. For example, Buccinum undatum, the Cape Ann "Periwinkle," might well serve as food, 
since in Europe it has long been thus utilized. In all the coast towns of England and Scotland 
this shell is peddled for food, under the name "Whelk" or " Wilk," and it may be bought at all 
the street-comers in the poorer quarters of London, where it is esteemed a great luxury. Our 
Whelk might equally well be eaten, and is very common northward from Cape Cod to the arctic 
regions, living chiefly on rocky shores, but also inhabiting muddy bottoms. It is thus accessible 
to castaways upon bleak arctic coasts where no other edible shellfish of consequence occurs, and 
ought not to be forgotten by those who take the risk of shipwreck in Labrador or Greenland. 

•Nest demanding attention are two of the largest mollusks on the Atlantic coast north of the 
tropics — Fulgur carica and Sycotypus canaliculata. North of New Jersey these two are contused 
under the general names of " Periwinkle," " Winkle," and " Wrinkle." The former of these species 
extends "northward only to Cape Coil," and is uncommon beyond Long Island, while the second 
is of more frequent occurrence in Vineyard Sound and along the Connecticut shore than south- 
ward. Both are carnivorous, and find in the Oysters a quiet, easy prey ; they consequently do 
great damage to the beds, and are properly destroyed by fishermen whenever a chance occurs. 1 
believe this is especially true of the Sycotypus. On the coast of New Jersey and southward, 
where the Fulgur reaches an immense size, and is known as the "Conch," the oystermen complain 
very little of it. 

The Sycotypus is more common north of New York, though it does not exist at all beyond 
Cape Cod; while along the coast of New Jersey and southward it is the Fulgur which is charge- 
able with nearly all mischief perpetrated, since the other species is rarely seen. Occasionally, as 
Verrill mentions, specimens of both may be found crawling on sandy flats or in the tide-pools, 
especially during the spawning season, but they do not ordinarily live in such situations, but in 
deeper water, on hard bottoms off shore. It is needless to say that they do not burrow at all, 
though they are able to insert the posterior part of the foot into the sand sufficiently to afford 
them a strong anchorage against currents. A very soft or a very rocky bottom they equally 
avoid. 

The curious egg-cases of these mollusks, to which the names "sea-ruffle" and "sea-necklace" 
are often given by fishermen, always attract the attention of visitors to the sea side, who find 
them cast upon the beaches; and we can well echo the pious exclamation of the old historian of 
Martha's Vineyard, — "The Author of nature makes a wonderful and copious provision for the 
propagation of this worm!" The eggs are discharged in a series of disk-shaped, subcircular, or 
lenilbnn, yellowish capsules, parchment-like in texture, united by one edge to a stout stem of the 
same kind of material often a foot and a half or two feet in length. "The largest capsules, about 
an inch in diameter, are in the middle, the size decreasing toward each end. On the outer border 
is a small circular or oval spot, of thinner material, which the young ones break through when 
they are ready to leave the capsules, each of which, when perfect, contains twenty to thirty or 
more eggs or young shells, according to the season." Verrill adds interesting particulars, as 
follows: 

" Dr. Elliott Cout>s, who has observed Fulgur carica forming its cases at Fort Macon, North 
Carolina, states that I he females bury themselves a few inches below the surface of the sand on 
the Hats that ire uncovered at low water, and remain stationary during the process. The string 



REPRODUCTION OF THE CONCH. 695 

of capsules is gradually thrust upward as fast as formed, and finally protrudes from the Burface ol 
the sand, and, when completed, lies exposed on its surface. The string begins as a single shred, 
two or three inches long, without well-formed eases; the firs! cases are small and imperfect in 
shape, but they rapidly increase in size and soon heroine perfect, the largest being in the middle; 
the series ends more abruptly than it began, with a few smaller and less perfect capsules. The 
number of capsules varies considerably, bu1 there arc usually seventy-five to one hundred or 
more. At Fort Macon Dr. Cones observed this species spawning in May, bill at New Haven the\ 
spawn as early as March and April. It is probable that the period of spawning extends over 
several mouths. Mr. Sanderson Smith thinks that they also spawn in autumn on Long Island. It 
is not kuowD how long a time each female requires for the formation of her string of capsules. 
There are two forms of these capsules, about equally abundant in this region. In one the sides of 
the capsules are nearly smooth, but the edge is thick or truncate along most of the circumference, 
and crossed by numerous sharp transverse ridges or partitions, dividing it into facets. Dr. 
Cones states that these belong to Fulgur carica. An examination of the young shells, readj 
to leave the capsules, confirms this. The other kind has larger and thinner capsules, with a thin, 
sharp outer edge, while the sides have radiating ridges or raised lines. Sometimes the sides 
are unlike, one being smooth and more or less concave, the other convex and crossed by ten 
or twelve radiating, elevated ridges extending to the edge. This kind was attributed to Fulgur 
carica by Dr. G. H. Perkins, and formerly by Mr. Sanderson Smith, but a more careful examina- 
tion of the young shells, within the capsules, shows that they belong to Sycotypus canaliculata. ,,x 

Eggs so exposed are subject to numberless accideuts, being drifted ashore, ground to pieces 
by storms, and no doubt eaten by bottom-feeding fishes, so that only a few eggs out of the 
hundreds in each "necklace" are ever born, or, accomplishing that, are able to survive the perils 
of unprotected youth and grow to adult age and strength. Having once done so, however, this 
mollusk probably lives to a very great age. 

An examination of a specimen of either of these species will show that in both the 
muscular part is large and strong and the mouth powerful. The food of the Conch being mainly 
the flesh of other mollusks, its method of killing them is one of brute strength, since it is unpro- 
vided with the silicious, file-like tongue by means of which the small " Drills" set at naught the 
shelly armor of their victims. The Conch is a greater savage than that. Seizing upon the unfor- 
tunate Oyster, unable to run away, he envelops its shell in the concave under surface of his foot, 
and, by just such a muscular action as you would employ in grasping an object in the palm of 
your fist, crushes the shell into fragments and feasts at leisure on the flesh thus exposed. Where 
Oysters or other prey are abundant, this operation is quickly repeated and vastly destructive. 
One planter in the upper part of Buzzard's Bay, where these pests are very troublesome, thought 
one Winkle was capable of killing a bushel of Oysters in a single hour. They do not confine 
themselves to Oysters altogether, of course; any mollusks or other marine animal, sluggish and 
weak enough to be caught and broken up, suffers from their predacity. I was told in New 
Jersey, by an intelligent man, that the Conch would even draw the Razor-shell out of his burrow 
and devour it. If this be true, no doubt the Soft Clam also falls a victim to the same marauder. 
The Quahaug is generally safe in his massive shells. 

The oyster-beds most subject to attack and harm by the Winkles and Conchs are those 
planted in water which is quite salt, as is the practice in New England and Long Island Sound. 
The beds of the Great South Bay, Staten Island, and the southern Jersey coast are well protected 
by the outer beaches from the sea, and to these barriers owe their immunity from the Fulgur, 
while the Sycotypus, though present inside the beaches, seems to do small damage. Oystermen 
1 Eeport U. S. Fish Commission, part i, 1873, pp. 355, 356. 



696 NATURAL HISTORY OF AQUATIC ANIMALS. 

will tell you, also, that beds which are disturbed from time to time by the planter will suffer more 
harm than neglected beds, especially in summer. Of course it is to be expected, as reported, that 
where planting has gone on for many years, there these predatory mollusks have visibly increased 
in numbers. 

In regard to ridding our beds of this pest, 1 can only advise, as heretofore, that every effort 
be made to destroy every specimen taken and every "necklace" of eggs which can be got hold of. 
The trawl, tangles, etc., recommended for the suppression of star-fishes, in my Report to the 
Census Bureau upon the Oyster Industries, would take up these eggs at the same time, and thus 
do double service. Persistent fighting is the only resource against this enemy, however, as in 
the case of others. 

Some points of minor interest may be mentioned before leaving this subject. Both of these 
shells were used by the Indians of the coast ceremonially, and as material for the making of white 
wampum, their money of inferior value, which consisted of bead-shaped sections of the central 
column of the shell. From them, also, were fashioned sundry articles of service and ornament, 
such as trowels, spoons, and dippers; they are sometimes even yet called "ladle shells." The 
Indians ate the animals, too, when hard pressed for food, anil have been followed in this practice 
by the whites, to some extent. De Voe says they used sometimes be sent into Catharine Market, 
New York, from Long Island, and found sale; "but," he adds, "they are not generally relished, 
being somewhat strong flavored. They are mostly used by the poor who live near the coast." 
Several foreign mollusks, not greatly different, are eaten — generally being boiled — and perhaps 
proper cooking would make these Conchs more palatable than they have hitherto proved. 

Under the name of "Drfll" is included a numerous class of univalve mollusks, which are 
carnivorous in their tastes, and armed with a tongue-ribbon so shaped and so well supplied with 
flinty teeth that by means of it they can file a round hole through an enemy's shell, — a habit 
which renders them of much account in the fisheries, where the victim they attack is the valuable 
Oyster, as they are sadly prone to do. The mode in which the entrance is made has been clearly 
described by Rev. Samuel Lockwood, as follows: 

"The tongue is set with three rows of teeth like a file; it is, in fact, a tongue-file, or dental 
band, and is called by conchologists the lingual ribbon. . . . Having with the utmost care 
witnessed a number of times the creature in the burglarious act, I give the following as my \ Lew 
of the case: With its fleshy disk, called the foot, it secures by adhesion a firm hold on the upper 
part of the Oyster's shell. The dental ribbon is next brought to a curve, and one point of this 
curve, on its convex side, is brought to bear directly on the desired spot. At this point the teeth 
are set perpendicularly, and the curve, resting at this point, as on a drill, is made to rotate one 
circle, or nearly so, when the rotation is reversed; and so the movements are alternated, until, 
after long and patient labor, a perforation is accomplished. This alternating movement, I think, 
must act favorably on the teeth, tending to keep them sharp. To understand the precise movement, 
let the reader crook his forefinger, and, inserting the knuckle in the palm of the opposite hand, 
give to it, by the action of the wrist, the sort of rotation described. The hole thus effected bj 
the drill is hardly so much as a line in diameter. It is very neatly countersunk. The, hole 
finished, the little burglar inserts its siphon or sucking-tube, and thus feeds upon the occupant of 
the house into which it has effected a forced entrance. To a mechanic's eye there is something 
positively beautiful in the symmetry of the bore thus effected — it is so 'true'; he could not do it 
better himself, even with his superior tools and intelligence." 

These small "Snails," "Drills," "Borers," and "Snail-bores," as they are variously called, 
belong to several species of Xatica, Purpura, Anachis, Astyrw, Tritia, Ilyanassa, etc.; but the master 



DESTRTJCTIYENESS OF THE COMMON DRILL. 697 

and most destructive, as well as most abundant of them all, is the Urosalpinx dnerea of Stiuipson. 
It is this which is the common "Drill" of the oyster-beds; and it is its eggs, laid in small vase- 
shaped capsules, which are often found attached in groups to the under surfaces of stones. 
Several of the small mollnsks mentioned above lay eggs in this wa\ , but tin- I bill's capsules have 
very short stalks, or are almost sessile, and are compressed with an ovate outline, while angular 
ridges pass down their sides. The natural home of the Drill is the tide-pools and weedy borders 
of rocky shallows, where barnacles, hydroids, anemones, rock-loving limpets, and other associated 
forms that find shelter among the algaa afford it abundant food. Though this is precisely where 
the Mussels grow till the rocks are almost black with them, it is said that they are never attacked 
by the Drills. 

The Urosalpin.v sometimes strays to the oyster-beds, but is usually carried there with the seed 
supplies, and, finding plenty of nourishment, lives and increases. Though its multiplication is not 
very rapid, it is fast enough to make it a very serious obstacle to success in the course of a few 
years. In nearly every case I was told that formerly there were no Drills, but now the oyster- 
beds were overrun. This was reported in particular of the Great South Bay of Long Island and 
at Keyport, New Jersey. I heard less of its ravages in New Jersey, except in the Delaware ; but 
in Chesapeake Bay nearly every dredge-haul in any part of Maryland or Virginia waters brings 
them up. The Potomac seems to be the district least infested. Of course, in such natural haunts 
as the rocky shores of Buzzard's Bay and Connecticut they would be present if there were no 
Oysters, and are all the harder to dislodge. 

Once having attacked an oyster-bed, they work with rapidity, and seem to make sudden and 
combined attacks at considerable intervals. Their disappearance from certain restricted localities, 
too, for a long time is unexplained. 

What is the best way to combat them, or whether there is any hope of ridding the beds of 
them, are questions often discussed by oyster-culturists. It is certain that a great deal of trouble 
might be avoided if care were exercised in culling seed to throw out — not into the water, but on 
the ground or deck — all the Drills, instead of carrying them to one's beds, dehberately planting 
them, and then grumbling at destruction which previous care would have avoided. It would cost 
less in point of mere labor, no doubt, to prevent this plague than to cure it when it became no longer 
endurable. Some planters clean up pieces of bottom very thoroughly before planting, in order to 
get all this sort of vermin out of their way, as well as to stir up the mud and fit it for the reception 
of spat. It is on hard bottom that Drills are especially troublesome, and here some planters go 
over the ground with a fine-meshed dredge in order to get them up, but they fail to catch all. 
This is done at Norwalk, Connecticut, I know, and the men who have steamers find in the celerity 
with which they are able to accomplish this sort of work a great argument against any restriction 
to exclusively sailing-rig. 

The Drill can be exterminated to a great extent, also, by diligently destroying its eggs. Small 
boys might well be paid to search for them and destroy them among the weedy rocks by the shore 
at low tide. A gentleman at Sayville, Long Island, assured me that in those years when eels 
were plentiful the Drills were kept down because the eels fed on their eggs. This gentleman said 
in the Great South Bay the Drills were nearly conquering the planters, and he advised the 
removal of all shells from the bottom of the bay, in order that the Drills might have nothing left 
on which to place their eggs. This might do there, where there are no rocks along the shore and 
the Drill is not native; but I doubt whether so sweeping a measure of protection could ever be 
carried out. 

On the Pacific coast Gastroelicena and various pholadiform mollusks are a great bane to the 



698 NATURAL HISTORY OF AQUATIC ANIMALS. 

oyster-beds, but they penetrate by digging burrows wherein their whole shell is lodged. Where 
large numbers of these are present, with the help of boring-worms and sponges, they may so 
riddle a reef as to cause its entire disintegration under the first gale. A fourth borer is Purpura 
lapillus, which is of interest in another direction. The famous Tyrian purple of ancient days— 
the regal dye that was deemed too splendid a color to be worn by any but kings and nobles- 
was produced from a sea-snail, and conchologists have busied themselves to discover which 
particular one. 

In the works of Pliny and Aristotle, the earliest sources of knowledge on the subject, the 
information is too vague to be relied upon. Dr. Eoth, of Munich, in a paper read before the Jeru- 
salem Literary Society, says that several years ago (previous to 1857) he found at Jaffa the 
Purpura patula, sought as food by the Christians during fast days : " On puncturing this animal 
there issued a greenish liquid, which, when exposed to the sunshine, changed to purple. This 
purple increased in brilliancy when it was washed." Comparing this with the accounts left by the 
ancients, Dr. Roth thinks the color he produced is evidently their blue color, for they had a blue- 
purple, a deep purple, and a red-purple. "Between Soor and Saida," according to the same 
author, "the Murex truncatus, or trunculus, is found in abundance, and its color is more brilliant 
than that of the Purpura. One of these Murex is sufficient to dye a square inch of cloth, which 
would require five individuals of Purpura patula. Wool takes the dye better than any other 
substance ; silk takes it with difficulty.'" 

Linton, in his work " On Ancient and Modern Colours," as quoted by Simmouds (" Commer- 
cial Products of the Sea," p. 304), states that the Purpura; of the best description were chiefly found 
on the rocks of Tyre, on the coast of Asia. They were also collected at Mininge, on the Grastulan 
shore in Africa, and on the coast of Laconia in Europe. The colors varied accordiug to the 
locality in which they were takeu, and also accordiug to the animal's haunt, as has since been 
proved by zoologists. Thus, when it lived among seaweeds or mud the juice it contained was 
comparatively worthless ; when among pebbles its quality was improved ; and the dye was best 
when the food and surroundings were varied. Researches carried still further proved that to 
produce the richest and most costly dye which art could exhibit, the liquid must be used in 
conjunction with that procured from other shell-fish. Just what the species were that were used 
it is now impossible to tell, but they were allied to Murex and Buccinum. Niter, urine, water, salt, 
and certain sea-weeds were also mixed with the Purpura liquor iu compounding certain tints. " In 
the reign of Augustus," says Simmonds. " one pound of wool dyed with the Tyrian purple sold for 
about £36 sterling [about $175]. We need not wonder at this enormous price when the tedious 
nature of the process is considered, and the small quantity of dye obtained from each mollusk. 
For fifty pounds of wool the ancients used no less than two hundred pounds of the liquor of the 
Murex and one hundred pounds of that of the Purpura, being six pounds of liquor to one of wool ; 
consequently the rich Tyrian purple fabrics vied iu value even with gold." 

The liquor was procured by placing the small shells in a mortar and crushing them. Animals 
extracted from the larger shells were added, and also urine, pure water, or water in which purple 
Snails had been allowed to putrefy. Iu this mixture the cloth was soaked and afterwards exposed 
to the light, sometimes under the influence of warmth to accelerate the process. 

It is said that the dyeing property is a transformation of uric acid into purpurate of ammonia, 
called murexide. This is a splendid substance when pure, presenting in one direction beautiful 
metallic green reflections, and in others browu and purple tints. Some chemists assert that it is 



1 Phipson: Utilization of Minute Life. London Groombridge & Sons, 1864, p. 144. 



SHELLS USED FOU CAMEO-CUTTING. 699 

to this substance that the iridescent plumes of humming-birds, pheasants, and peacocks owe their 
wonderful brilliancy. Mhrexide is now obtained not only from mollusks, but from guano, etc. 

Dyes from mollusks have been obtained in all ayes and almost all quarters <>t' (In 1 world, and 
not only our Purpura lapillus, but also another species which we share with ('.real Britain, the 
Whelk (Buccinum undatum), have been the subject of successful experiments of this sort. " 1 1' the 
shell of Purpura lapillus is broken, there is seen on the back of the animal, under the skin, a 
slender, longitudinal, whitish vein, containing a yellowish liquor. When this juice is applied to 
linen, by means of a small brush, and exposed to the sun, it becomes green, blue, and purple, and 
at last settles into a fine unchangeable crimson." The housewives of New England therefore have 
growing abundantly on their sea-side rocks little living bottles of indelible ink which cannot bo 
excelled by any manufactured product for either beauty or durability, since neither acid nor alkali 
will affect its color. 

On the Pacific coast occur shells of the genus OUvella, so called because they resemble small 
olives. There are three species, OUvella biplicata, 0. gracilis, and 0. dama. The first named of 
these shells certainly, and possibly the other two, now and then were made into money by many 
Californian tribes of Indians, which money circulated widely on the Pacific slope. The common 
Indian name for this OUvella money was " colcol." It was made by grinding off the apex or spire 
of the shells in such a way that they could be strung. They are still used by some tribes in the 
form of double necklaces as ornaments, but are regarded as of small value. Sometimes the shell 
was broken crosswise and ground into little disks which passed as coins. This money was very 
ancient and widespread through aboriginal traffic in connection with other forms of shell-money to be 
mentioned hereafter, and which the present writer has fully discussed in a paper on "Wampum" 
contained in the American Naturalist, 1 to which the reader is referred. 

Cameos are articles of ornament made by carving portions of various shells in such a way that 
a raised figure of one color shall be relieved against a ground of another tint constituting the under 
layer of the shell. These colors may vary — white on an orange ground, or on dark claret ; pale 
salmon-color on orange ; yellow on pink, etc. Anciently cameos were cut upon gems with immense 
labor, but latterly this easier imitation in shell has almost entirely superseded the intaglios in 
onyx, agate, and jasper. The cameo artists live mostly in London and Paris, and use several 
species of large shells that combine a white crust with a nacreous understratum of a different tint. 
Two only of these shells come from American waters, and these only touch our coast in tropical 
Florida — Cassis madagascariensis and Strombus gigas — the ''Helmet-shell" and the "Conch." 

Of the Helmet-shell several sorts are used in cameo-cutting. Our American example (which 
got its name, madagascariensis, through an error in regard to the locality of the type-specimen) 
has a blackish inner coat, called an " onyx " ground, and shows up white on a dark claret-color. 
It is known to the trade as the Black Helmet, and is highly esteemed by cameo-cutters. 

The Conch or Queen Conch {Strombus gigas) is of less account in cameo-making, because it 
affords a less quantity of surface suitable for the work — a portion of its broad, rose-tinted lip. 
Various other ornaments are often made from this and other large shells by turning and sawing 
with special machinery, and thus a large demand is created, which is satisfied chiefly through 
brokers in London and Liverpool. Just how many shells are sent to England annually it is 
impossible to tell; but the amount reaches some tens of thousands. There is also a large 
commerce in them both to Europe and to the United States to be used as ornaments alone, and to 
be given away by grocers and tea-dealers to promote their custom. In the West Indies, and on 

1 American Naturalist, xvii, May, 1883, pp. 467-479. 



700 NATURAL HISTOBY OF AQUATIC ANIMALS. 

many plantations in the Gulf States, the (Jonch is perforated at the apex of the spire, and forms 
a horn, used to call workmen in from the fields and at dinner. From fragments of this great 
mollusk, also, the Indians of Florida and the Antilles made their most esteemed beads and 
pendants. Oabeza de Vaca says that the columella of large Concha were chiefly available for this 
purpose. "These beads are more or less cylindrical or globular, aud always drilled lengthwise. 
Some are tapering at both ends, resembling a cigar in shape, and were two and one-half inches in 
length. The aborigines also made . . . peculiar pin-shaped articles consisting of a more or 
less massive stem which terminates in a round knob." 

The Strombus enters, when ground, into the manufacture of porcelain ; is extensively burned 
for lime; and is carefully calcined for medicinal purposes. There is also derived from it a 
secondary product of great value — the conch-pearl. When perfect, this pearl is described as either 
round or egg-shaped aud somewhat larger than a pea, of a beautiful rose color, and watered, that 
is, presenting, when held to the light, the sheeny, wavy appearance of watered silk. It is 
however, very rare to find a pearl which possesses all the requiremeuts that constitute a perfect 
gem, aud such proves an exceedingly valuable prize. Although many of these pearls are annually 
obtained by the fishermen in the Bahamas, not more than one in twenty proves to be a really 
good gem. Pink is the most common and only desirable color, although white, yellow, and brown 
pearls are occasionally found. Even among the pink ones there is usually some defect which mars 
their beauty and materially injures them ; some are very irregular in shape and covered apparently 
with knobs or protuberances; others are too small, while many lack the watering which gives 
them their great value and chief beauty. Most of the conch-pearls have been sent to London, 
and the demand for them is increasing; a few come to New York. 

Lunatia heros is very conspicuous along our coast, from the Gulf of Saint Lawrence to Cape 
Hatteras or beyond, wherever sandy shores and pure waters are to be fouud, and it is abundant 
and of very large size on the outer beaches of the coast of New Jersey. "When in motion the 
white soft parts are protruded from the shell to a remarkable extent and spread out broadly on 
all sides, so as nearly to conceal the shell; the foot is large, flat, and broadly expanded, with thin 
edges, aud by means of it the animal is able to burrow, like a mole, beneath the surface of the 
sand." This Snail, like many others of its tribe, drills round holes through the sides of various 
bivalve shells by means of the small flinty teeth on its ribbon like tongue, which acts like a rasp, 
and having thus made an opening it inserts its proboscis and sucks out the couteuts. All sorts of 
burrowiug bivalves in this way fall victims to this and its close ally, the Neverita duplicate. "Nor 
do I hey confine themselves to bivalves, but will drill any unfortunate Gasteropoda they may happen 
to meet, not even sparing their own young." Their usual haunts are away from the oyster-beds, 
however, so that, although they are a familiar sight in the dredge, the harm they do to this 
industry is of small account. 

Following this in the list come various small shells, such as those of the genera Litloriiut, 
Jtissoa, Rfelampw, and Bittium, of which it can only be said that they serve a very useful purpose as 
scavengers, swarming upon the mud exposed at low tide and greedily devouring carrion of fishes, 
etc., which would otherwise decay and pollute both air and water. The same good service is done 
by the small mollusks previously noticed as "Borers," aud many following. 

This brings us to the beautiful family of Abalones, Ormer-shells, or Sea cars, in whicli there is 
a very large trade on the Pacific coast, under the industry of the Chinese there, to which will be 
given a special chapter. 

In the Limpets (Crepidula and Acmea) the oystermen consider they have a friend, since when 
they see these clustering upon their planted beds they look forward to a profitable harvesl the 



THE EDIBLE LAND SNAILS. 701 

coming autumn. A Californian species (Fissurella aculeata) was used as money by some of the 
native, red men of the coast. 

In respect to the odd pill-bug-like shells of the several species of Chiton of our eastern 
shore I can say nothing; but in Bermuda a larger Chiton is gathered lor soup, and the broth is 
said to be very good. The Bermudans also make use of thai Chiton as a hail with which to take 
the large lobsters of the island, themselves intended to act as bait lor fishes. 

The sea surrounding Bermuda is of great transparency, and the fishermen can readily discern 
the long horns of the lobster protruding from his hiding place among the rocks, at a considerable 
depth. The ouly plan by which they can get him, however, is to entice him out of his refuge. 
To do this they mat together a quantity of Chitons until they have formed a hall several inches in 
diameter. To this they attach a string, and— having previously baited the bottom in front of the 
lobster's den and left him to enjoy it until his confidence was captured — let the ball dangle before 
his nose. Thinking this only a larger tidbit, he seizes it, and, to his amazement, is swiftly drawn 
up to daylight and torn to pieces to form a lure for equally unwary fishes. 

" These shells have been called by different names, all, however, indicative of their form, such 
as 'Wood-louse,' e Sea-boat,' ' Battle-snake's Tail,' ' Lobster's Tail,' ' Sea-bug,' and ' Sea-caterpillar.' 
The French say that the animal may be eaten, and we are told that the Iceland fishers swallow it 
raw to quench thirst, and pretend that it is good, also, against sea-sickness." The American 
Indians of the Northwest coast, South Sea Islanders, and other savages find the Chiton acceptable 
as food. 

In Melamprus bidentatus we have a small shell which swarms upon the mud and among the 
eel-grass, affordiug food to many fishes and acting as a scavenger of the marshes. In addition to 
this, it has a place in these remarks because it belongs to the division of air-breathing mollusks, 
and introduces not only the fresh-water shells Limnea, Physa, Planorbis, etc. that feed the inland 
fishes, but also the edible land Snails.* To these latter, interesting mollusks I lately devoted a 
chapter in my "Friends Worth Knowing," 1 from which I quote whatever applies to the present 
purpose : 

" Snails, being great eaters, meet their just reward in being eaten. The paludine forms are 
sought after by all sorts of water birds, particularly ducks and rails; while the thrushes and 
other birds crush the shells of the laud Snails and extract their juicy bodies. The woodland 
birds, however, will not eat. the naked-bodied Slugs : the slime sticks to their beaks and soils their 
feathers; but the ducks seem to have no such dainty prejudices. Some mammals, like the 
raccoons and wood-rats, also eat them ; insects suck their juices, and the carnivorous Slugs prey 
upon one another. Lastly, man, the greatest enemy of the brute creation, employs several species 
of Snails for culinary purposes. By the Bomans they were esteemed a great luxury, and portions 
of plantations were set apart for the cultivation of the large, edible Helix pomatia, where they 
were fattened by the thousand upon bran sodden in wine. From Italy this taste spread throughout 
the Old World, and colonies of this exotic species, survivors of classical 'preserves,' are yet found 
in Great Britain wher" *he Boman encampments were. They are still regarded as a delicacy 
in Italy and France, the favorite method of preparation being to boil in milk, with plenteous 
seasoning. Frank Buckland says that several of the larger English species are excellent food for 
hungry people, and recommends them either boiled in milk, or, in winter, raw, after soaking for 
an hour in salt and water. Some of the French restaurants in London have them placed regularly 
upon their bills of fare. Thousands are collected annually and sent to London as food for 
cage-birds. Dr. Edward Gray stated, a few years ago, that immense quantities were shipped 

1 Harper and Brothers, New York, 1880. 



702 NATURAL HISTORY OF AQUATIC ANIMALS. 

alive to the United States 'as delicacies'; but I am inclined to consider this an exaggeration 
growing out of the fact that, among our fancy groceries, 'a few jars of pickled Snails, imported 
from Italy,' figure as a curiosity, rather than something needed for the table. The same author 
records that the glassmen at Newcastle once a year have a snail feast, collecting the animals 
in the fields and hedges on the Sunday before. 

"Mr. W. G. Binney, for whom a sirup of Snails was prescribed by two regular physicians in 
Paris in 1863, points out how old is the belief that land mollusks possess valuable medicinal 
qualities. In the Middle Ages the rudimentary shell of the Slug acquired a high rank among the 
numerous bezoars and amulets which were supposed to protect the body from evil influences, and 
to impart health and activity. The accounts of these virtues, copied from one author to another, 
have perpetuated the early superstitions until it is difficult to overcome them by the light of the 
present day, when, even in England, Snails are supposed to possess a useful power in cases of lung 
trouble. A full relation of all the absurdities which gained credence would form a curious and 
marvelous page in the history of credulity. They have, also, from very early times, been used in 
the preparation of cosmetics ; and no longer than two or three centuries ago the water procured 
from them by distillation was much celebrated, and employed by ladies to impart whiteness and 
freshness to the complexion. Finally, I hear that there is celebrated in Rome, even now, a 
midsummer festival, upon which occasion all family feuds may be made up, or any differences 
between friends easily adjusted, since that is the spirit of the day; and a sign or token of this 
renewed friendship and good-will is the present of a Snail from one party to the other, or an 
exchange of mollusks between them. The symbolism and virtue reside in the alleged amicable 
influence of the head and 'horns' — why, perhaps comparative mythologists may be able to tell us. 

" In this country no such fanciful notions have ever gained credence. The Snails are too 
habitually hidden to attract the attention of any but a few ; and even when their existence is 
known, they are unfortunately regarded with such a disgfist as would preclude any acceptance of 
them, either for food or medicine." 

In Thomas De Voe's "Market Assistant," p. 312, is the following information, which refers to 
about the year I860 : " From the French journals we learn that there are fifty restaurants and 
more than twelve hundred private tables in Paris where Snails are accepted as a delicacy by from 
eight to ten thousand consumers. The market price of the great vineyard Snails is from 2 francs 
50 centimes to 3 francs 50 centimes (47 to 66 cents) per hundred, while those of the hedges, woods, 
and forest bring only from 2 francs to 2 francs 25 centimes (38 to 43 cents). Snails are, and have 
been for several years, imported [into New York] from Europe, but are principally used by 
foreigners. They are generally stewed after having been scalded out of their shells.*' 

The customhouse counts this import among "fancy groceries,'' so that no separate record is 
obtainable of the amount consumed. In the case of several of the large Southern species, such as 
the Apple-snail (Ampularia), the Bulimi, and the large pond Snails, their remains in the shell- 
heaps show that in prehistoric time they formed a regular part of the food of the red men. The 
Seminoles, of Florida, and various native races west of the Rocky Mcui^iuus, eat them yet. 

207. THE WING-SHELLS— PTER0P0DA. 

The Pteropods, or wing-footed mollusks, are a small group which swim freely throughout the 
broad ocean. Their shells are of small size, fragile, and semi-transparent. They form, therefore, 
available food for a large number of surface-feeding fishes, and particularly of the cetacea ; the 
right whale, indeed, is said to live almost wholly upon certain species of them which abound in 



THE BIVALVE MOLLUSKS. 703 

arctic seas and swarm near the surface at night, so thai he need only drop his jaw and engulf 
fchem by the hundred in his capacious mouth as he swims along with his head half out of water. 

Probably the same thing is true of the other bahenoids. 

208. THE TUSK-SHELLS— S0LEN0C0NCHA. 

The class denominated in Professor Verrill's Check List Solenoconcha includes only one 
mollusk that may concern us at present— Dentalium. This mollusk (chiefly D. pretiosum) occurs 
all along the northern Pacific coast of America, and is known to Americans as the "Tusk-shell," 
toEussians as "Sookli," and to the Alaskan Indians as "Hya-qua." From Northern California 
all the way to the arctic regions the coast tribes collected this shell, polished it, and arranged it 
on strings as money— a circulating medium of trade, similar to the wampum of the eastern coast. 
There were certain rules as to fineness, arrangement, size, and measurement, which decided the 
value of the shells before and after stringing ; and so useful was this allocochiclc, as the California 
Indians called it, that the Hudson's Bay Company and other traders adopted it as current coin 
in their buying and selling of peltries and provisions. 

The strings of Dentalia were also worn as necklaces by the women, or twined in the hair of 
both sexes; as trimming for garments, and ornaments for horse-trappings and the equipments of 
war and the chase. Among other methods of employing them to enhance personal charm was to 
insert two of them, point to point, from opposite sides, through a perforation in the partition 
which separates the nostrils, which decoration was further increased by sticking a bright feather 
in the large end of each of the hollow shells. This money is going out of use now, and only the 
old Indians, conservators of ancient customs, attempt to hoard it up. A full account of it may r be 
found in the article upon u Wampum" already alluded to, printed in "The American Naturalist" 
for May, 1S83. 

209. THE BIVALVES— LAMELLIBBANCHIATA. 

It is in the class of plate-gilled or lamellibranchiate mollusks, more popularly known as 
" bivalves," that we find the most examples of direct utilization by man, or immediate contribu- 
tion to the. fisheries. Bivalves are widespread and well-known. They afford luxuries as well as 
solid nourishment for our tables, enter largely into manufactured products, serve as ornaments, 
and are so beloved by food-fishes generally that they are useful as bait. 

The partial list of bivalved mollusks that are ascertained to enter into the diet of Ameri- 
can food-fishes includes the following, mainly from the northern Atlantic coast as in the case of 
the gasteropods, and is instructive as showing how extensively fishes depend upon molluscan 
food: 

Ensatella americana, Crytodaria siliqua, Mya arenaria, Spisula ovalis, Macoma sabulosa, Angulus 
tener, Petricola pholadiformis, Venus mercenaria, Cyprina islandica, Gardium pinnulatum, Gardium 
islandicum, Gryptodon Gouldii, Yenerieardia borealis, Astarte quadrans, Nucula proximo,, Nucula 
tennis, Yoldia limatula, Yoldia sapotilla, Yoldia myalis, Yoldia thraciformis, Leda tenuistilcata, 
Argina pexata, Mytilus edulis, Modiola modiolus, Modiolaria discors, Crenella glandula, Pecten 
tenuicostatus, Pecten islandicus, Pecten irradians, and Ostrea virginica; to which must be added 

Unio, Anodonta, and other fresh-water bivalves, and the brachiopods Bhynconella psittacus and 

TerebratuMna septentrionalis. 

In this Hot many species are of importance otherwise, and some worth notice, although not 

fed upon by fishes, are not mentioned ; the first to be named in this latter class is the dreaded 

Ship. worm (Teredo), of which there are seven species in the United States : 



704 NATURAL HISTORY OF AQUATIC ANIMALS. 

Teredo navalis, Linue. Cape Cod to Florida ; Sweden to Sicily. 

Teredo norvegica, Speugler. Cape Cod northward. 

Teredo megotara, Hartley. Massachusetts Ray to South Carolina. 

Teredo dilatata, Stimpson. Massachusetts to South Carolina. 

Teredo Thompsoni, Tryon. Cape Cod, Massachusetts. 

Xylophaga dorsalis, Forbes and Hanley. North Atlantic. 

Xylotrya fimbriate,, Jeffreys. Long Island Sound to Florida; British Columbia; Europe. 

The most commonly observed of these is the Teredo navalis. This is the same species that has 
attracted so much attention in Europe, during nearly two centuries, on account of the great 
damage that it has done, especially on the coast of Holland. Its history has been reviewed ;it 
length by Professor Verrill iu his " Invertebrates of Vineyard Sound," from which the present 
account is principally derived. 

"Although popularly known as the 'Ship-worm,' these creatures are not at all related to the 
worms, but are true mollusks, quite nearly allied, in many respects, to the common 'Long Olanv 
(Mya) and to the Pholas. Like those shells, the Teredo excavates its holes or burrows merely for 
its own protection, and not for food; but the Teredo selects wood in which to form its holes, and 
when these have been excavated it lines them with a tube of shelly material. The holes are very 
small at the surface of the wood, where they were formed by the young Toredos, but they gradually 
grow larger as they go deeper and deeper into the wood, until they sometimes become ten inches 
or more iu length and a quarter of an inch iu diameter; but the size is generally not more than 
half these dimensions. The holes penetrate the wood at first perpendicularly or obliquely, but if 
they enter the side of the timbers or planks across the grain the burrows generally turn horizon- 
tally in the direction of the grain a short distance beneath the surface, unless prevented by some 
obstruction, or by the presence of other toredo tubes, for they never cross the tubes of their 
companions or interfere with each other in any way, and there is always a thin layer or partition 
of wood left between the adjacent tubes. It is, however, not accessary thai they should follow 
the grain of the wood, for they can and do penetrate it in every direction, and sometimes not more 
than half the tubes run iu the direction of the grain, and they are often very crooked or even 
tortuous. They rapidly form their burrows in all kinds of our native woods, from the softest pine 
to the hardest oak, and although they usually turn aside and go around hard knots, they are also 
able to penetrate through even the hardest knots in oak ami other hard woods. The Teredos 
grow very rapidly, apparently attaining maturity in one season, and therefore, when abundant, 
they may greatly damage or completely destroy small timber in the course of four or five months, 
and even the largest piles may be destroyed by them in the course of two orthree years. 

"When removed from its tube the animal is found to have a very long, slender, smooth, soft, 
whitish body, tapering somewhat toward the outer or posterior end, which hasa muscular, circularh 
wrinkled collar, by which the animal is, when living, attached to the inside of the shelly lining of 
its tube. To the inside of this collar two shelly plates, known as the 'pallets,' are attached by 
their slender basal prolongations; their outer portions are broad and Hat, and more or less 
emarginate or two-horned at the end. These are so connected with the muscles that when the 
animal withdraws its tubes into its hole the free ends of these pallets are made to fold together 
and close the opening, thus serving as an operculum to protect the soft tubes against enemies of 
all kinds. Between the bases of the pallets arise the siphonal tubes, which are soft and retractile, 
united together for half their length or more, but separate and divergent beyond; they are nearly 
equal, but the ventral or branchial tube is perhaps a little larger than the other, and is fringed 
with a few small papillae at the eud. The tubes are white or yellowish, sometimes speckled with 



HABITS OF THE SHIP-WORMS. 705 

reddish-brown. At the anterior end of the body, and farthest from the external opening of tin- 
hole, is seen the small but elegantly sculptured white bivalve shell. The shell covers t 1j» ■ month 
and palpi, liver, foot, and other important organs. The foot is a short, stout, muscular organ, 
broadly truncate or rounded at the end, and appears to be the organ bj means of which the 
excavation of the burrow is effected. The shell is covered by a delicate epidermis, and probably 
does not assist in rasping off the wood, as main have supposed. The gills are long and narrow, 
inclosed mostly in the naked part of the body, and are reddish-brow n in color. 

" The Teredos obtain their microscopic food in the same manner as other bivalve mollusks, viz, 
by means of a current of water constantly drawn into the branchial tube by the action of vibrating 
cilia within; the infusoria and other minute organisms are thus carried along to the mouth at the 
other end, while the. gills are supplied with oxygen by the same current ; the return current 
passing out of the dorsal tube removes the waste water from the gills, together with the faeces 
and excretions of the animal, and also the particles of wood which have been removed by the 
excavating process. 

"As the animal grows larger the burrows are deepened, the lining of shelly matter increases 
in length and thickness, the shell itself and the pallets increase in size, and the terminal tubes 
grow longer. But as the orifices of the terminal tubes must necessarily be; kept at the external 
opening of the burrow, the muscular collar at the base of the tubes constantly recedes from the 
entrance, and with it the pallets ; at the same time imbricated layers of shelly matter are usually 
deposited in the upper end of the shelly tube, which are supposed to aid the pallets in closing the 
aperture when the tubes are withdrawn. When the animal has completed its growth, or when it 
has encountered the tubes of its companions and cannot pass them, or when it approaches the 
exterior of a thin piece of wood and cannot turn aside, it forms a rounded or cup-shaped layer 
of shelly matter, continuous with the lining of the tubes and closing up the burrow in front of 
its shell. Sometimes it retreats and forms a second partition of the same kind. 

"This species produces its young in May and probably through the greater part or all of the 
summer. The eggs are exceedingly numerous, probably amounting to millions, and they are 
retained in the gill-cavity, where they are fertilized and undergo the first stages of their develop- 
ment. The embryos pass through several curious phases during their growth. In one of the 
early stages they are covered with fine vibrating cilia, by means of which they can swim like 
ciliated infusoria ; later they lose these cilia and develop a rudimentary bivalve shell, which is at 
first heart-shaped, and the mantle begins to appear and larger retractile cilia develop upon its 
edge, which serve as organs for swimming ; but at this period the shell is large enough to cover 
the whole body when contracted. In this stage they swim actively about in the water ; later the 
cilia become larger, a long, narrow, ligulate foot is developed, by means of which they can creep 
about and attach themselves temporarily to solid objects; the shells become rounder, a pair of 
eyes and organs of hearing are developed. After this the little animal begins to elongate, the 
locomotive cilia are lost, the eyes disappear, and the mature form is gradually assumed. These 
young Teredos, when they finally locate upon the surface of wood-work and begin to make their 
burrows, are not larger than the head of a pin, and consequently their holes are at first very 
minute, but owing to their rapid growth the holes quickly become larger and deeper." ' 

This species is very abundant along the southern coast of New England, from New York to 
Cape Cod, wherever submerged wood-work, sunken wrecks, timber buoys, or floating pieces of 
drift wood occur. It also infests the bottoms of vessels not protected by sheathing. At Province- 
town, Cape Cod, about forty feet of the end of the steamboat wharf was so weakened by its 

1 Report, U. S. Fisli Commission, part i, 1873, pp. 384-386. 
45 P 



706 NATURAL HISTOEY OF AQUATIC ANIMALS. 

borings that it completely gave way under a shipload of merchandise stored upon it. This pest 
is not confined to pure sea-water, but occurs in the piles and timbers of wharves in harbors that 
are not only brackish, but also muddy and contaminated with sewage. Capt. B. J. Edwards 
told me that formerly when the cedar channel buoys in Buzzard's Bay, Massachusetts, were not 
taken up they would last not more than two years, owing chiefly to the attacks of this Teredo; 
but under the present system there are two sets of buoys, which are alternately taken up and 
put down every six months. After a set has been allowed to dry thoroughly they are scraped 
to remove the barnacles, etc., and then receive a thorough coat of verdigris paint each time 
before they are put down. With this treatment they will last ten or twelve years, but they 
are more or less perforated and injured every year, until finally they become worthless. This 
statement does not apply to the spar-buoys, which are taken up only once a year, in April 
and May. Captain Edwards says that the Teredos would destroy an unpainted spar-buoy in 
one year, but when painted with verdigris they will only work where the paint becomes rubbed 
off. They first attack buoys or piles just below the water's edge, but eventually will destroy 
the entire submerged wooden portion. Commenting upon this information, Professor Verrill says: 

"Inasmuch as the Teredos produce their young all through the summer, and they develope to 
a very large size in ope season, it is evident that the best time to take up the buoys would be in 
midsummer, before the early crop of young have grown large, and leaving too little time for the 
later crop to become large, in the buoys thus put down, before winter, when most of them would 
probably be killed by the cold weather. In this way the damage might be materially diminished, 
if not inconsistent with the other duties of the officers of the vessels employed iu this service. 
There are, as yet, no means of estimating the extent of the damage done to our wharves, shipping, 
etc., by this and the various other species of Teredo found on our coast, but, judging from theii 
abundance along the whole coast, it is much greater than is generally supposed. 

"The Teredo navalis is also abundant on the coast of Europe, from the Mediterranean and 
Black seas to Christiania and the coasts of Great Britain. Its habits have been quite thor- 
oughly investigated by several Dutch naturalists, owing to the greai damage that it has done 
on their coast, at times even threatening a general inundation of the country by destroying the 
wood-work of the dikes. This Teredo occupies a zone of considerable breadth, for it often lives 
considerably above low-water mark, and extends several feet below it, even to the depth of lour 
teen feet, according to some writers. 

"The best remedies in common use to resist or prevent its attacks are copper sheathing, used 
chiefly on vessels; broad-headed nails, closely driven, used for piles and timbers; creosote and 
coal-tar, frequently applied. The various poisonous substances that have been applied to timber 
for this purpose, however useful they may be in other respects, have little or no effect on tin- 
Teredo, for it does not depend upon the wood for its food, and even protects its body externallj 
with a layer of shell, lining its holes. The only remedies that are likely to succeed are those 
calculated to prevent the lodgment and entrance of the young ones beneath the surface. Even 
creosote, thoroughly applied under pressure at the rate of ten pounds per square loot, has been 
found insufficient to prevent their attacks, for piles thus treated at Christiania were found by Mr. 
Jeffreys to be filled with the Teredo within two years after they were put down. 

" Several other species of Teredo also occur on this coast. The Teredo megotnra has been fount 1 
in floating pine wood at Newport, Rhode Island, and in cedar buoys, etc., at New Bedford, Massa- 
chusetts; as well as in Massachusetts Bay, at Provincetown, and other places; it is also found as 
far south as South Carolina at least. This species sometimes grows to a large size, forming tubes 
at least eighteen iuches long. It sometimes occurs, also, in the piles of wharves in this region 



THE OLAMS. 707 

/Vineyard Sound, Massachusetts]. The Teredo Thomsoni has beeu fonnd in great numbers in 
the marine railway aud also iu cedar buoys at New Bedford. It has also been found at 
Provincetown in a whaling-ship that had cruised in the West Indies. 

"The Xylotnja fimbriate is very similar to the common Toredo, except that it lias long, oar- 
shaped pallets, with slender stalks; the blade is flattened on the inside and convex externally, 
and consists of ten to twelve or more funnel-shaped segments which set one into another; their 
margins project at the sides, making the edges of the blade appear serrated. This species appears 
to be indigenous on this coast. It has beeu found living in a sunken wreck in Long Island Sound, 
near New Haven, and I have also taken it from the oak timbers of a vessel, the "Peterhoff," 
employed in the blockading service, during the late war, on the coast of the Southern States. It 
grows to a rather large size, often forming holes a foot or more in length aud a quarter of an inch 
in diameter, though usually smaller. The pallets are sometimes half an inch long." 

Less likely to be mistaken for worms, but ecpially clever at boring, is a group of shells called 
Pholads, from the Greek word <pu>\£u>, lurking. They perforate all substances that are softer than 
their own valves, and some that seem to be harder. Woodward says: "It is to be remarked that 
the condition of the Pholades is always related to the nature of the material in which they are 
found burrowing; in soft sea-beds they attain the largest size and greatest perfection, whilst in 
hard and especially gritty rock they are dwarfed in size and all prominent points and ridges 
appear worn by friction." The Pholads have white she]ls, generally very thin but hard and 
strong, and adorned with rasp-like sculpture. It was supposed formerly that the excavation was 
made by twisting and moviug this rough shell in the burrow; but the muscular, club-shaped foot 
is no doubt the instrument of abrasion. 

We have upon the east coast three species, but none of them are of practical importance. 
They might become available for food, however, since the same mollusks are eaten in the southern 
counties of England, where they are called "Piddocks," and some cousins {Zirjphcea crispata, 
Platydon cancellatus, etc.) are esteemed delicacies ou the coast of California under the name of 
'•Date-fish." Other west-coast species {Navea, Qastrocliama, etc.) are enemies of the Oyster, 
Abalone, and other mollusks which themselves have a commercial importance, since they burrow 
into their shells aud so ruin them for service to man. There is, nevertheless, an attendant 
advantage in this, since in a state of nature the Pholads thus break to pieces and tend to level 
reefs that would prove obstructive to navigation, particularly in the case of coral banks. When 
the object leveled is an expensive dike or breakwater, however, the result is exactly reversed, as 
,it is very likely to be where man's arts attempt to change the natural arrangement of things. 

Our Eazor-shell (Ensatella americana) is frequently used for food in Europe and in New 
England, and its valves have occasionally been applied to artistic service. It passes under the 
various names of "Eazor-fish," " Razor-clam," "Knife-handle," etc., and is enticed from its sandy 
burrow by sprinkling salt upon the sand under which it lies, or is rooted out with a spade. John 
Josselyn, Gent., records that its " shell, calcin'd and pulveriz'd, is excellent to take off a pin and 
web, or any kind of filme growing over the eye." The Californian Razor-fish (Siliqua patula) is 
also edible. 

Next upou the list comes the "Soft Clam," "Long Clam," or "Nanninose" (Mya arenaria), 
dear to New Englanders and only less numerous than the Hard Clam in the markets of New York 
and Philadelphia. This Clam lives just beneath the surface of the sand and mud above low-water 
mark, and is easily dug out with a hand-shovel. A very large class of persons all along the shore 
from Maine to Delaware derive their living wholly or in part by digging it and shipping to city 
markets. This is chiefly the case north of New York, however. On the northern coasts of New 



708 NATURAL HISTORY OF AQUATIC ANIMALS. 

England immense quantities of tins bivalve are collected and salted to be used as bait in the 
cod fishery. Statistics and a full discussion of the habits and artificial culture of this Clam will 
be found in the special chapter devoted to the Clams. 

Washed up by storms from the deep sands — down at least to ten fathoms below the low-water 
line— and hence known as the ''Beach," "Sea," or "Surf" Clam, the huge Spisula solidissima 
furnishes occasional repasts to the dwellers along the whole Atlantic shore. It is chiefly eaten in 
Massachusetts, however, and its flesh is tough and by some persons considered unwholesome. It 
is often cast up in such great quantities as to become available for manure, mixed with various 
other marine animals of all sorts and sizes and much sea-weed. The large, smooth, white valves 
are collected in considerable quantities to be decorated inside with pictures in oil or India ink, 
which are again sold in the picture stores, often for a good price. This Clam is also preserved as 
bait. On the Pacific coast an allied species [Spisula falcata) serves the various purposes to 
which the eastern one is applied. 

Following this comes the Quahaug ( Venus mercenaria), which is known in the markets as 
" Hard Clam," " Round Clam," or, in New York, simply " Clam." From Cape Cod to Florida it is 
very abundant, but must be gathered by raking, since it does not burrow in the shore-sands like 
the Soft Clam. A commerce still larger than in the case of the Soft Clam is carried on with 
this species as bait, and also for food, in which respect it ranks next to the Oyster in the United 
States. 

On the Pacific coast — where eastern shell-fish are constantly sent for transplantation and for 
immediate consumption — there are various bivalves used as food, such as Semele decisa, the " Flat 
Clam"; Macoma nasuta, the "Tellens," of San Francisco; Schizothcerus Nuttalii, the "Gaper"; 
Chione succincta, aud allied species, which replace eastern "Little Necks"; and Saxidonms aratv»s, 
to relish which was learned from the Indians. 

In regard to this latter mollusk (Saxidomus aratus) it is interesting to note rhat its shell was 
broken into pieces by the Indians of the California coast aud worked into flat, circular disks by 
rubbing upon stone. Eighty of these disks strung upon sinews were in recent use by the Indians 
of Lake County, California, as a medium of exchange in trade, and were valued at one dollar. In 
Sonoma County Saxidomus gracilis seems to have served the same purpose. 

Another form of aboriginal money was made from the valves of the ponderous lien Clara of 
southern California- (Pachydesma crassatelloides), already mentioned. This money was called 
" hawolc? and took the shape of perforated disks which could be strung as beads. The larger 
pieces, according to Stearns, were worth twenty-five cents, and were cut from the thicker parts 
of the shell ; while the thinner portions supplied beads worth only four cents each. Further 
information will be found upon this in my magazine article above referred to. 

The Pachydesma and its neighbor, the Cardium Nuttalii, are considered edible by the west 
coast people; but on the Atlantic shore, where occur several large species of "Cockle" (as the 
members of the genera Cardium, Astarte, Venerieardia, and the like, are called), they are rawly or 
never used as food. This neglect seems curious, since this mollusk is eaten in great abundance in 
England, and may be bought everywhere in London during summer. " Prodigious quantities of 
this shell-fish are also consumed in Holland, where their cheapness recommends them to the 
common people as a principal article of food during the winter." In New England ( 'yprina islandica 
is eaten now aud then, but bears a poor reputation in comparison with the Quahaug. In the 
Southern States the large "Painted Clam " (Callista gigantea) is equally available as food, and the 
Gnathadon cuneat us of the Gulf of Mexico is already an article of diet, as well as useful in road- 
making, to which utility many other mollusks contribute in all sea-shore towns. 



THE MUSSELS. 709 

These thick-shelled bivalves disposed of, a large group of thin-shelled mpllusks deserve 

notice. Foremost among these arc the Mussels, which air of several kinds. In Europe the MyHhis 
edulis (which is not different from our common Black Mussel of botu the easl and west coasts) liolds 
an important place among sea-foods. In is:;; the mussel fishery of Prance alone was worth over 
800,000 francs ($160,000). In that country they are regularly bred in inclosures of sea-water, 
upon frames and hanging ropes constructed for the purpose, and manj persons are employed. 
In England^ Scotland, Ireland, along the Mediterranean, in the West Indies, and along the whole 
circumference of South America, edible species of one name or another grow. Our MyUlus edulis 
is circumpolar in its distribution, and is excessively numerous at all rocky points suitable Cor its 
growth. In New York it is pickled in large quantities and shipped throughout the interior ol the 
country. Its shells are extensively used by oyster-planters as a cultch upon which to catch young 
Oysters, and when polished are made into paint-holders for artists and various articles of bijouterie 
and personal ornament. The American Indians and the native New Zealanders used them as 
tweezers in pulling out their beards. 

m Mussels of a different sort are the Modiola plicatula, the Modiola modiolus, the Modiola hamatrn, 
and Modiola ca/pax; the first two are of the northern Atlantic, the third is more southern, and 
the fourth a native of California. These are sometimes eaten, but are not considered so good as 
the M. edulis. On the coasts of New Jersey and Long Island, however, incredible quantities are 
gathered from the banks at the inlets through the outer beaches where they grow, and are spread 
upon sea-shore farms as manure. In gathering this fertilizer a large number of vessels and men 
find irregular employment at times when they would otherwise be idle. 

Another important bivalve in a commercial way is the Scallop, fisheries for which flourish in 
Long Island Sound, Narragansett Bay, and elsewhere. Large fleets of vessels are engaged in 
summer in dredging for these shell-fish. The powerful central muscle by which the animal opens 
and closes its shells forms the edible portion, the rest being discarded. These white fragments are 
to be seen piled upon platters or strung in strings as a constant delicacy in all our markets. The 
common Scallop of commerce is the Pecten irradians. Years ago the very large species, Pecten 
islandicus, an inhabitant of Eastern Maine and the Bay of Fundy, used to be obtained, and was 
highly prized for its flavor, but it has long been too rare to serve any purpose other than as a 
curiosity to conchologists. A more common and useful species, north of Gape Cod, is Pecten tenni- 
costdtus, which supplied the Indians with a culinary instrument, and is good food. 

" Scallop shells were formerly worn by pilgrims on their hat or the cape of their coat, as a 
mark of their having crossed the sea for the purpose of paying their devotions at the holy shrine 
in Palestine ; in commemoration of which they are still preserved in the armorial bearings of many 
families of distinction whose aucestors had performed that ceremony. From its use by cooks 
now, this shell has given the name to ' scalloped' Oysters. In early times, when plates and drink- 
ing- vessels were not so plentiful as they are now, the concave or hollow valve of the Scallop served 
as a cup, and the flat valve for a plate. The idea has even been carried out by our pottery man- 
ufacturers, and plates and dishes have been molded after the forms of bivalve shells. Reticules, 
needle-books, pincushions, and other articles are made by shell-dealers with the scallop shell." 

Of both the Scallop and the Mussel a special account will be given in another place, con- 
sidering the value of each commercially. 

The fresh-water bivalves belonging to the large family of the Unionidce ought not to be 
omitted in this review. To the raccoon, otter, muskrat, aud many other mammals and birds, as well 
as to the fishes, they are a steady source of food. Observing this, the Indians adopted them from 
the earliest prehistoric times as edible, and enormous heaps of shells upon the banks of many 



710 NATURAL HISTORY OF AQUATIC ANIMALS. 

of our interior rivers, especially in Pennsylvania, the Ohio Valley, and the Southern States, show 
how extensively and constantly they were sought. White men occasionally eat them, and in case 
of extreme hunger would perhaps pronounce a roasted Unio or Anodonta good. Some years ago a 
great fnrore was created by the discovery of a fine pearl in one of the Unios of North Carolina — a 
thing likely to happen in the case of any of them, since they have an interior which is often as finely 
nacreous as that of the Mother-of-pearl Oyster of the Gulf of California. Hundreds of persons 
immediately began searching the rivers all over that region, and total extirpation of the poor Mus- 
sels was prevented only by the discouragement of finding few pearls and these of insignificant 
size. It is probable that from the heavier species, in captivity, good pearls might be obtained 
artificially by following the plan pursued by the Chinese with their sea Pearl-oystei\ The experi- 
ment is worth trying. 

Shells of fresh-water Mussels are frequently worked up into pocket-books and other fancy arti- 
cles, as in the case of the Mytilus. When the brown epidermis is removed a beautiful iridescent 
polish is obtainable. There are almost innumerable varieties of these fresh-water Mussels, and 
full cabinets have a considerable value. • 

The manufacture of jewelry and shell-flowers consumes large quantities of small shells and 
and the polished opercula of large ones, chiefly derived from Florida. It is said that in Loudon 
about a million of the commoner sorts are sold to street-sellers and country peddlers, who retail 
them to be made into fancy work and as objects of curiosity. The same thing is frequently .seen 
in the United States, though more commonly in the shape of the traveling dealer who brings 
a large and varied stock to a country town, hires a shop for several weeks, and sells his shells 
mainly by auction. 

The spread of commerce and improved facilities for dredging have made species once rare now 
common ; but astonishing prices, reaching hundreds of dollars for a single, specimen, in some cases 
were paid by owners of conchological cabinets for rare species half a century ago. This stimulated 
research and distributed much money among sea-side collectors. Even now dealers in objects of 
of natural history derive a large profit by importing shells whose only value is their scientific 
importance; while the institutions devoted to their study and the books to which an interest in 
conchology have given rise are entitled to a money estimation not to be despised. 



A CONTRIBUTION TO THE LIFE-HISTORY OF THE OYSTER. 

(Ostrea virginica, Gmelin, and 0. edulis, Linn.) 

By John A. Kyder. 

210. OUTLINE SKETCH OF THE COARSER ANATOMY OF THE OYSTER. 

" The general structure of au Oyster maybe roughly represented by a long, narrow memorandum 
book, with the back at one of the narrow ends instead of at one of the long ones. The covers of 
such a book represent the two shells of the Oyster, and the back represents the hinge, or the 
area where the two valves of the shell are fastened together by the hinge ligament. This ligamenl 
is an elastic, dark-brown structure, which is placed in such a relation to the valves of the shell 
that it tends to throw their free ends a little apart. In order to understand its manner of working, 
open the memorandum book and place between its leaves, close to the back, a small piece of 
rubber to represeut the ligament. If the free ends of the cover are pulled together the rubber 
will be compressed and will throw the covers apart as soon as they are loosened. The ligament 
of the oyster-shell tends, by its elasticity, to keep the shell open at all times, and while the 
Oyster is lying undisturbed upon the bottom, or when its muscle is cut, or when the animal is 
dying or dead, the edges of the shell are separated a little. 

"The shell is Uned by a thin membrane, the mantle, which folds down on each side, and may 
be compared to the leaf next the cover on each side of the book. The next two leaves of each 
side roughly represent the four gills, the so-called 'beard' of the Oyster, which hang down like 
leaves into the space inside the two lobes of the mantle. The remaining leaves may be compared 
to the body or visceral mass of the Oyster. 

"Although the Oyster lies upon the bottom, with one shell above and one below, the shells 
are not upon the top aud bottom of the body, but upon the right and left sides. The two shells 
are symmetrical in the young Oyster, but after it becomes attached the lower or attached side 
grows faster than the other, and becomes deep and spoon-shaped, while the free valve remains 
nearly flat. In nearly every case the lower or deep valve is the left. As the hinge marks the 
anterior end of the body, an Oyster which is held on edge, with the hinge away from the observer 
aud the flat valve on the right side, will be placed with its dorsal surface uppermost, its ventral 
surface below, its anterior end away from the observer, and its posterior end toward him, and its 
right and left sides on his right and left hands, respectively. 

" In order to examine the soft parts, the Oyster should be opened by gently working a thin, flat 
knife-blade under the posterior end of the right valve of the shell, and pushing the blade forward 
until it strikes and cuts the strong adductor muscle, which passes from one shell to another and 
pulls them together. As soou as this muscle is cut the valves separate a little, and the right 
valve may be raised up and broken off from the left, thus exposing the right side of the body. 
The surface of the body is covered by the mantle, a thin membrane which is attached to the body 
over a great part of its surface, but hangs free like a curtain around nearly the whole circum- 
ference. By raising its edge, or gently tearing the whole right half away from the body, the gills 



712 NATURAL HISTORY OF AQUATIC ANIMALS. 

will be exposed. These are four parallel plates which occupy the ventral half of the mantle cavity 
and extend from the posterior nearly to the anterior end of the body. Their ventral edges are 
free, but their dorsal edges are united to each other, to the mantle, and to the body. The. space 
above, or dorsal to the posterior ends of the gills, is occupied by the oval, firm adductor muscle, 
the so-called ' heart.' For some time I was at a loss to know how the muscle came to be called 
the 'heart,' but a friend told me that he had always supposed that this was the heart, since the 
Oyster dies when it is injured. The supposed 'death' is simply the opening of the shell when the 
animal loses the power to keep it shut. Between this muscle and the hinge the space above, the 
gills is occupied by the body, or visceral mass, which is made up mainly of the light-colored repro- 
ductive organs and the dark-colored digestive organs, packed together in one continuous mass. 

" If the Oyster has been opened very carefully, a transparent, crescent-shaped space will be 
seen between the muscle and the visceral mass. This space is the pericardium, and if the delicate 
membrane which forms its sides be carefully cut away, the heart may be found without any 
difficulty, lying in this cavity, and pulsating slowly. If the Oyster has been opened roughly, or 
if it has been out of water for some time, the rate of beating may be as low as one a minute, 
or even less, so the heart must be watched attentively for some time in order to see one of 
the contractions." 1 

The dark-purple scars near the centers of both valves are simply the areas covered by the 
attachments of the adductor, which is composed of a vast number of extremely fine muscular 
fibers, which collectively pass straight across the space between the inside of the valves, being 
firmly fixed at either end of the latter. The tendency to separate the valves at their free borders, 
inherent in the 1 igament, is balanced or counteracted by the muscle. The head end of the animal 
lies close against the hinge, the point where, as previously described, the two valves are firmly 
fixed to each other by a dark-brown, crescent-shaped body, the ligament, which, while it serves to 
attach, also tends, by reason of its elastic properties, to cause the valves to separate at their free 
borders in order to allow the passage of the water inward to the gills, and of food to the mouth, 
while it also allows the water which has passed through the gills to escape by way of the cavity 
above the gills which is prolonged into the cloaca, carrying along with it, in its outward passage, 
the fasces from the vent. The foregoing lines fairly describe the mechanism of the shell and in 
part the physiological significance of the same. 

The structure of the shell is laminar, or, in other words, it is composed of numerous layers of 
a material identical in composition with chalk, deposited one on the other by the mantle, the organ 
which builds the whole shell in this way, the chalky substance being derived from the fluids of the 
animal, which in turn derives it from its food. These layers, deposited as they are internally, in 
a horny organic matrix, as growth proceeds project in succession pa St each other at the free edges 
of the valves and external surface of the shell, so that the successive deposits may readily be 
distinguished on its external surface, giving rise to a very rough imbricated appearance of the 
edges of the layers on the outside. Attempts which I have made to determine the age of Oysters 
from a supposed periodic deposition of the shelly material, corresponding to the years of its age, I 
find to be impracticable. 

The structure in the layers of the shell of the chalk or calcic carbonate is minutely prismatic 
Nathusius-Konigsborn has found that certain portions of the shell of the European Oyster contain 
very minute air spaces. Both native and foreign species are found to have hollow cavities in the 
valves, usually containing water. 



1 W. K. BROOKS : Development of the American Oyster. Studies from the Biological Laboratory of Johns Hopkins 
University. X o. IV. 1880, pp. 5-7. 



THE ANATOMY OF THE OYSTER. 713 

" In front of the gills, that is, between them and the hinge, there are four flesbj ttaps— the 
lips— two on each side of the body. They arc much like the -ills in appearance, and thej are 
connected with each other by two ridges which run across the middle of the body close to the 
anterior end, and between these folds is the large oval mouth, which is thus seen to be situated, 
not at the open end of the shell, but as far away from it as possible. As the Oyster is immm ahh 
fixed upou the bottom, and has no arms or other structures for seizing food and carrying it to the 
month, the question how it obtains its food at oncesuggests itself, [fa fragment of one of the gills 
is examined with a microscope it will be found to be covered with verj small hairs, or cilia, 
arranged in rows. Each of these cilia is constantly swinging back and forth, with a motion 

something like that of an oar in rowing. The motion is quick and strong i le direction and 

slower in the other. As all the cilia of a row swing together, they act like a line of oars, only t bey 
are fastened to the gill, and as this is immovable, they do not move forward through the water, but 
produce a current of water in the opposite direction. This action is not directed by the animal, 
for it can be observed for hours in a fragment cut out of the gill, and if such a fragment be supplied 
with fresh sea-water, the motion will continue until it begins to decay. While the Oyster lies 
undisturbed ou the bottom, with its muscle relaxed and its shell open, the sea-water is drawn on 
to the gills by the action of the cilia, for although each ciliurn is too small to be seen without a 
microscope, they cover the gills in such great numbers that their united action produces quite a 
vigorous stream of water, which is drawn through the shell and is then forced through very small 
openings on the surfaces of the gills into the water-tubes, inside the gills, and through these tubes 
into the cavity above them, and so out of the shell again. As the stream of water passes through 
the gills the blood is aerated by contact with it. The food of the Oyster consists entirely of minute 
animal and vegetable organisms and small particles of organized matter. Ordinary sea- water 
contains an abundance of this sort of food, which is drawn into the gills with the water, but as the 
water strains through the pores into the water-tubes, the food particles are caught on the surface 
of the gills by a layer of adhesive slime which covers all the soft parts of the body. As soon as 
they are entangled the cilia strike against them in such a way as to roll or slide them along the 
gills toward the mouth. When they reach the anterior ends of the gills they are pushed off and 
fall between the lips, and these again are covered with cilia, which carry the particles forward 
until they slide into the mouth, which is always wide open and ciliated, so as to draw the food 
through the oesophagus into the stomach. Whenever the shell is open these cilia are in action, 
and as long as the Oyster is breathing a current of food is sliding into its mouth. 

"The cilia and -particles of food are too small to be seen without a microscope, but if finely 
powdered carmine be sprinkled over the gills of a fresh Oyster, which has been carefully opened 
and placed in a shallow dish of sea- water, careful observation will show that as soon as the colored 
particles touch the gills they begin to slide along with a motion which is quite uniform, but not 
much faster than that of the minute-hand of a watch. This slow, steady, gliding motion, without 
any visible cause, is a very striking sight, and with a little care the particles may be followed up 
to and into the mouth. 

"In order to trace the course of the digestive organs, the visceral mass may be split with a 
sharp knife or razor. If the split is pretty near the middle of the body, each half will show 
sections of the short, folded oesophagus, running upward from the mouth, and the irregular 
stomach, with thick, semi-transparent walls, surrounded by the compact, dark-greenish liver. 
Back of the liver and stomach the convoluted intestine will be seen, cut irregularly at several 
points by the section. 

"There are no accessory organs of reproduction, and the position, form, and general appear- 



714 NATURAL HISTORY OP AQUATIC ANIMALS. 

ance of the reproductive organ is the same in both sexes. There is no characteristic by which a 
male Oyster can be distinguished from a female, without microscopic examination. As the repro- 
ductive organ has an opening on each side of the body, it is usually spoken of as double, but in 
the adult Oyster it forms one continuous mass, with no trace of a division into halves, and extends 
entirely across the body and [against] the bends and folds of the digestive tract." ' 

(The last of the foregoing statements as to the impossibility of discriminating the sexes with- 
out the aid of the microscope is no longer true, though it was true at the time the above was 
written. The method of discriminating the sexes discovered by the writer is discussed in another 
portion of this sketch of the history of the Oyster.) 

The stomach is pretty definitely marked off from the other portions of the digestive tract. It 
may be said to be that portion of the latter which is surrounded by the liver. The portion of the 
intestine immediately following the short widened region which we regarded as the stomach is the 
most spacious portion of the gut, and in it is lodged a very singular organ which has been called 
the "crystalline style." This is an opalescent rod of a glass-like transparency and gelatinous 
consistence which measures, according to the size of the Oyster, from half an inch up to one and 
a half inches in length. Its anterior end is the largest, and in a large specimen measures nearly 
an eighth of an inch in diameter, but at its posterior end is scarcely half as thick; both ends are 
bluntly rounded. I fell into an error in supposing that this style was lodged in a special pouch 
or sac as described in ray report to the Maryland commissioner in 1S80. The "crystalline style" 
really lies in the first portion of the intestine and extends from the pyloric end of the stomach to 
the first bend of the intestine, where there is a marked constriction of the alimentary canal. It 
appears therefore to be a sort of loose valve in the cavity of the gut; its function may be to 
prevent coarse particles of food from passing, or it may in some way assist digestion. In speci- 
mens hardened in acid or alcohol this rod is destroyed, or at least disappears, so that I have been 
unable to find it. The greater portion of its substance is apparently made up of water. 

The peculiar d ouble induplication of the wall of the intestine is described in another place. 
The faecal matters are extra ded in the form of a demi-cyliuder, with one side excavated in a groove- 
like manner. This shape of the faecal matters is due to the presence of the double fold. The fseces 
themselves are composed of extremely fine particles of quartz or sand grains, the tests of diatoms, 
organic matters, humus, cellulose, fragments of the chitinous coverings of some of the minute 
worms and articulates, etc., which have been swallowed and digested by the, animal. The anus 
is situated on the dorsal side of the great adductor muscle where the intestine ends. 

The organs of sensation of the Oyster, though not very highly developed, are of sufficient 
importance to merit attention. The auditory sense, although I have never been able to disseel out 
the auditory vesicles, I am satisfied exists, because one cannot noisily approach an Oyster bank 
where the Oysters are feeding without their hearing so that instantly every shell is closed. The 
tentacles of the mantle are often extended until their tips reach beyond the edges of the valves. 
If the an inial in this condition is exposed to a strong light the shadow of the hand passing over it 
is a sufficient stimulus to cause it to retract the mantle and tentacles and to close its parted valves. 
The mantle incloses, like a curtain, the internal organs of the creature on either side, and lies next 
the shell, and, as already stated, secretes ami deposits the layers of calcic carbonate composing 
the latter. The free edges of the mantle, which are purplish, are garnished with small, highly 
sensitive tentacles of the same color. These tentacles are ciliated and serve as organs of touch, 
and also appear to be to some extent sensitive to light. 

1 W. K. Brooks: Op. cit., pp. 8-10. 



THE INTERNAL STRUCTURE OF THE OY.S I II, 715 

The nervous system of the Oyster is very simple, and, as elsewhere stated, is to some extent 
degenerate, in character. It is composed of a pair of ganglia or knots of nervous matter, which lie 

just over the gullet, and from these a pair of nervous cords puss backward, on ach side, i" 

join the hinder pair which lie just beneath the adductor muscle. The mantle receives uerve 
branches from the hindmost ganglia or knots of nervous matter; these, as their centers, control the 

contraction and elongation of the radiating bundles of muscular libers. ;is well as I hose which lie 
lengthwise along the margin; the former contract and withdraw the edges of the mantle from the 
margin of the shell, while the latter in contracting tend to crimp or fold its edges. The tentacles 
are mainly innervated by fibers emanating from the hindmost ganglia, while the internal organs 
are innervated from the head or cephalic ganglia. The hind ganglia also preside over the 
contractions of the great adductor muscle. The nerve threads which radiate outward from it to 
the tentacles dispatch the warnings when intruders are at hand that it must contract and dose 
the shells. 

211. THE MINUTE ANATOMY OF THE OYSTER. 

There is a spacious segmentation cavity developed in the embryo which becomes the 
subdivided body-cavity — schizoccel of later stages. Between the ectoderm and endoderm the 
mesoblastic tissue is developed apparently by proliferation, so that the segmentation or body 
cavity becomes in part obliterated. The mesoblast of .the embryo formed as above stated is tbe 
tissue from which the mesenchyme or connective tissue of the adult is developed. The blood 
channels or canals are developed in the mesenchyme of the adult; — mesoblast of the embryo. 
The large, coarse vesicular connective tissue cells form a sort of trabecular network of pillars and 
transverse supports between and around which the sanguineous fluids circulate. Tbe blood 
channels or canals are developed directly from the spaces between the columns and their 
conjoining masses of connective tissue cells; an exception to this is found only in the structure 
of the anterior and posterior aorta?, the heart, and branchiocardiac vessels, which have proper 
walls lined with endothelial cells. Throughout the greater part of its extent the mesenchymal or 
connective tissue is spongy, its cells being built around complex anastomosing spaces for the 
blood. There is, therefore, a true schizoccel developed in the Oyster; it has been formed as the 
mesoblastic tissue has grown into the segmentation cavity and subdivided the latter into haemal 
canals and spaces. The blood cells originate in all probability in the same way. These are 
amoeboid, colorless, and measure about one three-thousandth of an inch in diameter. The vascular 
ehaunels have no specialized endothelial walls in the mesenchymal parts of the body. 

The adductor muscle of the shell and the radiating muscular bundles running from the 
insertion of the former to the edge of the mantle are derived from the mesoblastic cells of the 
embryo, the observations of Dr. Horst on this point having, I think, completely set at rest what 
was formerly a matter of theory. The radiating muscular bundles — pallial muscles — of the adult 
lie just beneath the epiblast or epithelium on the outer sides of the mantle leaves. These pallial 
muscles in the embryo are represented by two sets of dorsal and ventral muscular bundles, the 
functions of which are to retract the velum into which they are inserted. The muscular fibers of 
the walls of the heart are not striated and decussate in every direction. The inner walls of the 
heart are crossed in various directions by muscular bands or trabecule, and a more or less 
complete muscular septum divides the ventricle in the median line; the heart is, therefore, 
approximately four-chambered. 

The mesenchymal or mesoblastic tissues comprise the great bulk of the body of the animal, 
and extend out into and form the greatest proportion of the thickness of the mantle, and also 



V16 NATURAL HISTORY OF AQUATIC ANIMALS. 

down into the branchial sacs between their epiblastic or epithelial, ciliated, external walls. It 
also forms the principal bulk of the thick vertical, transverse septa which subdivide the branchial 
pouches internally, and forms likewise the bulk of the branchial filaments themselves. These 
latter are numerous and give the surface of the gills their furrowed or plaited appearance. The 
individual plaits or ridges seen in section are found to be quite complex and to be themselves 
compoundly ribbed and to have chitinous rods embedded in their substance just beneath the 
external epithelium. These rods run lengthwise through the substance of the branchial riblets. 
The branchial capillaries are excavated in the mesenchymal or connective tissue of the branchial 
filaments or tentacles, between which there are numerous openings or ostia for the passage of the 
water from the inferior portion of the pallial chamber into the gill cavities in order to effect 
respiration. It is difficult, however, to make this arrangement understood without the aid of 
figures. 

The mesenchyme also gives support to all of the visceral structures, the ultimate secretory 
follicles or saccules of the liver being imbedded and supported by it. The same is true of the 
generative structures and the intestine. No portion of the walls of the stomach, oesophagus, or 
hepatic ducts can be found the walls of which do not lie directly in contact with this mesenchymal 
or mesoblastic tissue. It also extends out into and forms the greater proportion of the substance 
of the palps or lips of the Oyster, and is very spongy and highly vascular in this region. The 
internal or oral surface only of the palps or lips are closely plaited with numerous folds of ciliated 
epithelium. These folds may number from one hundred and twenty-five or more. The surface of 
the palps in the immediate vicinity of the mouth is not plaited or folded. 

The mesenchymal cells are much larger than either the epithelial or endothelial cells, and will 
average one five-hundredth of an inch in diameter. They inclose in all cases, both in winter and 
summer, a large, irregular nucleus from which a complex network of intracellular granular fibrils 
radiate in all directions through the enveloping cellular substance. At one side of the nucleus 
there are always one or more accessory bodies, perfectly globular, which complicate the character 
of the nucleus in a singular manner. These vesicular, very hygroscopic, meseuchymal or connective 
tissue elements are not fat-cells, as has been erroneously supposed by Brooks. Their nuclei are 
invariably central and not parietal in position, as in fat-cells. These cells are probably very 
hygroscopic, as would appear judging from their singular appearance under the microscope. They 
appear to be widely distributed in the molluscous invertebrates; they were originally named 
"vesicular connective tissue cells "by the histologist Schaefer. An Oyster may in the summer 
season absorb water and swell up so as to fill up almost the whole cavity of the shell, and when 
opened it may lose so much blood and water in the course of half an hour that it will have shrunk 
to one-tenth of its original bulk. This is a common occurrence, and is explained by the prob- 
able hygroscopic character of the connective tissue cells and the spongy nature of the whole 
mesenchyme which consists of these elements. This also explains why it is that Oysters may be 
much swollen in a short time by osmotic action, when immersed in water of a less specific gravity 
than the sea-water from which they were first taken. The process has nothing in common with 
what might be called fattening, as we shall see hereafter. 

There is an apparent atrophy or wasting away of the mesenchyme of the body-mass and 
mantle during the spawning season, with a great concomitant development of the reproductive 
follicles or tubules. In winter the reproductive follicles atrophy, when the mesenchyme again 
increases in bulk in the body-mass and mantle. It also undergoes another remarkable series 
of changes corresponding to summer and winter. In summer it acquires an almost glass like 
transparency, so that the mantle, palps, and superficial portions overlying the viscera become 



THE IXTEE/NAL STRUCTURE OF THE OYSTER. 717 

translucent. In this condition, if the reproductive glands are undeveloped, the dark mass of 
the liver may be seen through the body walls. Towards the autumn, on the other hand, the 
connective tissue cells acquire a milky opacity and greal solidity as compared with their watery, 
transparent condition in summer. This last condition, which involves the whole mantle, the palps 
and superficial portions of the visceral mass, indicates to the oysterman the condition of fatness. 
The Oysters in this State are plump: do UOt SO readily diminish in hulk when removed from the 
shell as in summer; but that this change is due to storage of fatty matters l have not yet seen any 
evidence of any sort which would amount to proof. There is some oily matter in the Oyster, hut 
not enough to account for the changes which we have described. 

The atrophy of the connective tissue during the summer season would appear to indicate that 
the material for the genesis of the reproductive elements was derived from the mesenchyme, by a 
direct transformation of its substance in which the. generative follicles are imbedded. It is, in 
fact, the great development of the mesenchymal substance in the autumn and winter, when the 
reproductive function is in abeyance, that constitutes the condition of the animal known to oyster- 
men as fatness. These relations illustrate very beautifully a well-known physiological principle, 
viz, that nutritive processes are very intimately related to the reproductive; they are in fact inter- 
dependent. 

In summer, when the reproductive organs are gorged with their products, their follicles are 
crowded together into contact; in winter, in their atrophied condition, they lie imbedded in the 
superficial portion of the mesenchyme of the body-mass, the same as in summer, but. are much 
less developed, so as to ajjpear in sections like a very open network of strands of very small, 
nucleated, incipient embryo cells, the connection of which may be traced into the now collapsed 
and internally ciliated branches of the oviducts. All the parts of the reproductive apparatus are 
therefore present, in winter, but in an undeveloped condition. The oviducts branch and spread 
over each side of the body-mass just outside of the stratum of reproductive follicles and imme- 
diately beneath the mantle. They do not ramify through the substance of the reproductive organ, 
but traverse its surface, the follicles emptying their contents into the ducts by way of openings 
upon the inner faces of the latter. The main openings of the oviducts of either side open into the 
upper branchial cavity on either side of the hinder and ventral portion of the body-mass just 
below the muscle. There is but one opening on either side, notwithstanding the various state- 
ments to the contrary. 

Embryologically considered, the liver is an endodermal structure, a diverticulum of the 
stomach. The great bile ducts pass outward from the cavity of the stomach and subdivide again 
and again and end blindly in spacious ovoidal hepatic follicles, the simple, plicated walls of which 
consist of hepatic cells. The function of the liver is in all probability both excretory and secretory, 
and takes an all-important share in the processes of digestion. That the function of the liver is 
partially excretory is rendered all the more probable from the fact that there is little or no 
evidence of the existence of a renal apparatus or organ of Bojanus in the Oyster such as is found 
in other mollusks. Dr. Horst looked in vain for a rudiment of this last structure in the embryos 
of Ostrea edulis. Transverse sections through those portions of the body where it would most 
likely be found, made from both native and foreign examples, exhibit no structure in the least 
degree resembling what is regarded as the organ of Bojanus in Unio and Anodonta. 

The wall of the intestine, like that of the stomach,' is ciliated throughout, and is also of endo- 
dermal or hypoblastic origin. Its wall is folded inward along one side in a peculiar way, so that its 
lumen is more or less crescentic in cross-section. This arrangement, together with the very minute 
minor folds on its inner surface composed of long, columnar, ciliated epithelial cells, increases the 



718 NATURAL HISTOEY OF AQUATIC ANIMALS. 

amount of absorbing surface very materially. The internal surface of the stomach is also very 
much plicated; but here the folds are both large and conspicuous, with small folds often inter- 
vening. There are neither annular nor longitudinal muscular fibers in the wall of the intestine; 
the sole motive force used in the propulsion of the ingested food appears to be exerted by the 
ciliary covering which everywhere clothes the internal surface of the alimentary tract from the 
mouth to the anus. 

It would appear that the intestine makes two complete bends upon itself at a very early stage 
of embryonic life, according to the observations of Horst, long before it measures a ninetieth of 
au inch in diameter. The development of the liver seems to be at first lateral and somewhat 
ventral; an arrangement traces of which may still be noticed in cross-sections of the adult. 

The course of the intestine in the adult may be described as follows: 

The mouth is a wide opening between the upper median angles of the palpi: so wide, indeed, 
that the animal can scarcely be said to have au oesophagus; immediately follows the stomach, 
which is seen to have very pronounced folds internally, with a generally transverse direction, but 
two of these, which lie in a somewhat ventral position, are a pair of inward projecting folds which 
are themselves plicated. The intestine then follows an oblique course, downward and backward, 
when it makes a sharp bend returning beneath the floor of the pericardial space, passing obliquely 
upward and forward, somewhat to the right and dorsal of the stomach, when it crosses exactly 
over the mouth or very short gullet, passing downward to the left side of the animal, alongside 
and a little to the lower side of the stomach, when it again turns upward and passes over the 
pericardial space to end in the rectum just over the middle of the adductor muscle. The clusters of 
hepatic lobules or follicles dip down into the folds of the walls of the stomach, hut the liver does not 
follow the course of the intestine proper, which is provided internally with a curious pair of longi- 
tudinal and parallel folds, which project into the intestinal cavity and extend from the pyloric end 
to very near the anus. The presence of these folds gives to the faecal matters their singular appear- 
ance, which are not in the form of a cylinder as they leave the vent, but in the form of a tube with a 
part of one side removed. Tracing the course of the intestine by sections is not the proper way; 
they can be very easily dissected out for their entire length by means of the scissors and forceps. 

The systemic heart of the Oyster is that organ which serves to propel and redistribute the 
colorless blood of the animal through the body for its nourishment, and through the gills that the 
blood itself may discharge into the water the poisonous gases with which it is loaded in passing 
through the body, aud receive a fresh supply of oxygen as fresh supplies of water pass through 
the gills. The heart consists of three principal chambers; the upper, largest, whitish and partially 
divided by a median septum or partition, is the ventricle, and the two lowermost and smaller, 
brownish paired chambers are known as the auricles. These three chambers which comprise the 
heart of the Oyster lie in a crescent-shaped space, the pericardia] space, just forward of the 
adductor muscle. The ventricle is almost globular; its walls are made up of a delicate meshwork 
of unstriped muscular fibers, which are so interlaced as to be altogether untraceable. From the 
ventricle a great posterior and an anterior aortic vessel arises. These two vessels distribute the 
blood to the posterior and anterior portions of the body of the animal, but soon divide into paired 
vessels which traverse the mantle on either side both anteriorly and posteriorly, while one great 
median branch passes forward over the stomach. The blood is really distributed soon after 
leaving the main vessels, especially in the body through the spongy connective tissue spaces, as 
already described, and is collected into a great ventral canal from which a large part of it passes 
into the gills. From the four gills or branchial pouches the blood flows back to the ventricles 



SEX OP THE AMERICAN AND EUROPEAN OYSTERS. 719 

through six great branchiocardiac vessels, three of which arc arranged on each side; two pairs of 
these are anterior in position and one pair posterior. 

The circulation of the Oyster is quite different in character from that observed in a rertebrated 
animal. In the latter the heart pumps the purified blood to and through the gills before it passes 
to all parts of the body; in the Oyster, on the other hand, the fresh, pure blood is pumped by the 
heart from the gills before it passes to all parts of the body. 

A curious and interesting point which 1 think it desirable to mention, because I have not 
noticed that attention has hitherto been especially called to it, is the metamorphosis of the larval 
Oyster into the adult. A. de Quatrefages' has alluded to it, but not in explicit terms. I have 
shown in my sketch on the growth of the animal that the larval shell was quite different from that 
of the adult, in fact, more like a very diminutive pisidium than anything else. The metamorphosis 
of the larval shell, or rather its passage into that of the spat, is abrupt. Not so with the soft part s ; 
the oldest larva? yet studied by any competent biologist show that the mouth of the larva is 
placed on the ventral side of the embryo, and that the hinge is situated on almost exactly the 
dorsal or opposite side. The ventral position of the mouth of the larvae and its anterior or cephalic 
position in the adult show that a very important series of changes in the position of the viscera 
must take place between the time when the larva loses its principal embryonic features and 
acquires the adult arrangement and relations of its hard and soft parts. In other words, we are 
made aware, after instituting the foregoing comparison, that the Oyster actually undergoes a 
metamorphosis. 

If an Oyster be carefully opened it will be found that the animal adheres to the shell at four 
points, or at two points on either valve. The principal points of attachment are of course the 
insertions of the great compound adductor muscle, made up of two portions which may be 
distinguished by the color of the cut ends of the component fibers. The great shield-shaped 
purple areas on either valve mark the points of insertion of the great adductor in the American 
Oyster, and also in the Portuguese form, which resembles it considerably. In Ostrea edulis, or the 
European species, the insertion of the adductor muscle is very rarely colored, so rarely indeed that 
we may regard this feature as one of the specific marks of this form. But in both the American 
and the European species there is a second muscular attachment, as implied above, which appears 
to have been very generally overlooked. It is situated nearer to the hinge than to the great 
adductor, and is sometimes marked by a slight depression not over an eighth of an inch in its 
greatest transverse diameter. It gives attachment to a feeble muscular bundle which springs out 
of the mantle on either side of the visceral mass, and when the animal is torn loose a slight 
whitish scar on the soft part marks its position on the surface of the mantle. I have been 
informed that Mr. W. H. Dall, who has investigated the matter, has identified this muscle with 
the pedal muscle of some other acephalous mollusks. 

812. SEX, SEXUAL PRODUCTS, AND DIFFERENCE OF THE SEXUAL HABITS OF THE 
AMERICAN AND EUROPEAN OYSTERS. 

"The number of male cells which a single male will yield is great beyond all power of 
expression, but the number of eggs which an average female will furnish may be estimated with 
sufficient exactness. A single ripe egg measures about one five-hundredth of an inch in diameter, 
or five hundred laid in a row, touching each other, would make one inch; and a square inch would 
contain five hundred such rows, or 500 x 500=250,000 eggs. Nearly all the eggs of a perfectly 

'Metamorphoses of Man and the Lower Animals. Translated by H. Lawson, M. D., pp. 104-109. London, 1864. 



720 NATURAL HISTOEY OF AQUATIC ANIMALS. 

ripe female may be washed out of the ovary into a beaker of sea-water, and, as they are heavier 
than the sea-water, they soon sink to the bottom, and the eggs of a medium-sized female will 
cover the bottom of a beaker two inches in diameter with a layer of eggs one-twentieth of an inch 
deep. The area of the bottom of a beaker two inches in diameter is little more than three square 
incbes, and a layer of eggs one-twentieth of an inch deep, covering three square iuches, is equal to 
one three-twentieths of an inch deep and two square, and as a single layer of eggs is one five- 
hundredth of an inch thick, a layer three-twentieths of an inch thick will contain seventy-five 
layers of eggs, with 250,000 eggs in each layer, or 18,750,000 eggs. It is difficult to get the eggs 
perfectly pure, and if we allow one-half for foreign matter and errors of measurement, and for 
imperfect contact between the eggs, we shall have more than nine millions as the number of eggs 
laid by an Oyster of average size, a number which is probably less than the true number. 

" Mobius estimates the number of eggs laid by an average European Oyster at 1,012,925, or only 
oue-ninth the number laid by an ordinary American Oyster; but the American Oyster is very much 
larger than the European, while its eggs are less than one-third as large; so the want of agreement 
between these estimates does not indicate that either of them is correct. 1 Another estimate of 
the number of eggs laid by the European Oyster is given by Eyton (' History of the Oyster and 
Oyster Fisheries,' by T. C. Eyton, London, 1S58). He says. p. 24, that there are about 1,800,000, 
and therefore agrees pretty closely with Mobius. 

"An unusually large American Oyster will yield nearly a cubic inch of eggs, and if these were 
all in absolute contact with each other, and there were no portions of the ovaries or other organs 
mixed with them, the cubic inch would contain 500 3 , or 125,000,000. Dividing this, as before, by 
two, to allow for foreign matter, interspaces, and errors of measurement, we have about 60,000,000 
as the possible number of eggs from a single Oyster. 

"Although each male contains enough fluid to fertilize the eggs of several females, there does 
not seem to be much difference in the number of individuals of the two sexes. When a dozen 
Oysters are opened and examined, there may be five or six ripe females and no males, but in 
another case a dozen Oysters may furnish several ripe males but no females, and in the long run 
the sexes seem to be about equally uumerous. Oystermen believe that the male may be dis- 
tinguished from the female l>,\ certain characteristics, such as the presence of black pigment 
in the mantle, but microscopic examination shows that these marks have no such meaning, and 
that there are no differences between the sexes except the microscopic ones. It is not necessary 
to use the microscope in every case, however, for a little experience will enable a sharp observer 
to recognize a ripe female without the microscope. It a little of the milky fluid from the ovary of 
a female with ripe or nearly ripe eggs be taken upon the point of a clean, bright knife-blade and 
allowed to flow over it in a thin film, a sharp eye can barely detect the eggs as white dots, while 
the male fluid appears perfectly homogeneous under the same circumstances, as do the contents of 
the ovary of an immature female, or one which has finished spawning. Winn the eggs are mixed 
with a drop of water they can be diffused through it without difficulty, while the male fluid is 
more adhesive and difficult to mix with the water. By these indications I was able in nearly 
every case to judge of the sex of the Oyster before I had made use of the microscope. 8 

"During my investigations I submitted more, than a thousand Oysters to microscopic 
examination. My studies were carried on during the breeding season, and I did not find a single 



'Mobius' measurement, froni .15 to .18 millimeter, is given ( Austern und Austernwirthschaft, 1877) as the diameter, 
not of the egg, but of the embryo, but his figures show that the European Oyster, like the American, does not grow much 
during the early stages of development, but remains of about the same size as the egg. 

2 W. K. Brooks: op. tit., pp. 13-15. 



THE GBLL-STEUOTURB. OF THE OVSTF.lt. 721 

hermaphrodite. The male cells are so small compared with bhe eggs thai ii would be impossible 
to state that a mass of eggs taken from the ovary contained do spermatozoa, although bhej conJd 
not escape detection if they were at all abundant. 

"On the other hand, a single egg in the Held of the microscope, in a drop of male fluid, would 
be very conspicuous and could not escape detection ; and che fad thai uol a single ease of this 
kind occurred is sufficient to establish the distinctness of bhe sexes al bhe breeding season.'" 

Writing about this matter in 1880, 1 said: "TZo evidence to show that our Oyster is her- 
maphrodite was found during the entire season; nor were my searches for embryo or eggs in 
the mantle or iu the gills more successful than those carried on two years before by Professor 
Brooks. There is no doubt whatever that the Oyster of Europe nurses its young in its mantle 
or gills for some time; uor can we well question the very high authority of Mobius for saying 
that in most cases the sexes are separate, and that only one kind of products, viz, either eggs or 
spermatozoa, are at any time found in the generative organs. Lacaze-Duthier's observations seem 
to confirm the conclusions of Mobius." 

In reference to the structure of the cells which make up the body of the Oyster, as well as 
regarding the eggs, Dr. Brooks, on page 19 of his essay, writes as follows: 

" Each of these consists of a layer of protoplasm around a central nucleus, which, in the egg, 
is a large, circular, transparent body known as the germinative vesicle. Each cell of the body is 
able to absorb food, to grow and to multiply by division, and thus to contribute to the growth of 
the organ of which it forms a part. The ovarian eggs are simply the cells of an organ of the body, 
the ovary, and they differ from the ordinary cells only in being much larger and more distinct 
from each other ; and they have the power, when detached from the body, of growing and dividing 
up into cells, which shall shape themselves into a new organism like that from whose body the 
egg came. Most of the steps in this wonderful process may be watched under the microscope, 
and owing to the ease with which the eggs of the Oyster may be obtained, this is a very good egg 
to study." 

Brooks has represented the freshly laid ova of the Oyster with a spherical nucleus and 
nucleolus ; the former is large and clear, and is imbedded near the center of the egg, and inside of 
it the nucleolus is lodged somewhat to one side. I do not find the latter spherical, as described, 
but formed as if composed of a larger and smaller highly refringent pair of spheres, partly fused 
with each other, or of the same form as the nucleoli of the eggs of Anodonta as described by 
Flemming. 

Some investigations conducted under the auspices of the Dutch Government indicate that the 

structure of the generative organs of the European Oyster is not, as has been supposed, strictly 

follicular, but that they may rather be regarded as a mass of anastomosing tubes of irregular caliber. 

The complete proof of this has been developed by the writer in the course of investigations carried 

out upon our native Oysters, in which the generative organs were very immature during the 

winter season. Both Brooks and myself have spoken of the generative follicles as though they 

had been clearly made out ; it now appears that we will be compelled to modify our terminology 

somewhat, in the face of the fact that I have sections of the immature generative organ which 

exhibit it as a network of germinal cells, as well as sections of the mature organs which show a 

more or less distinct tubular structure opening toward the surface into the superficial or surface 

outgoing canals. At the same time the tubes show more or less extensive junction or anastomosis 

with each other at certain points along their length, with a general tendency to be disposed 

vertically to the surface of the visceral mass. This arrangement reminds one somewhat of the 

»W. K. Bkooks: op. tit., p. 35. 
46 F 



722 NAT DEAL HISTORY OF AQUATIC ANIMALS. 

more or less parallel disposition of the seminal tubules of the testicles or milt of fishes and higher 
animals. 

Tn microscopical cross-sections of the adult Oyster, whether it be male or female, the repro- 
ductive glands are found to be composed of a great number of minute pouches or follicles. In the 
gross arrangement of the follicles no difference between the sexes is discernible when thin sections 
are scrutinized with the microscope. Upon making an examination of the contents of the follicles 
with the microscope a great difference at once becomes manifest; in the male the spermatic 
particles in the follicles appear very finely granular, and if mature the tails or flagella of the 
spermatic particles tend to be directed toward the outlet of the follicle; in the female, sections of 
the follicles show the eggs in various stages of development attached by their narrow extremity 
to the walls of the reproductive saccules. The egg is pyriform in shape while still in the ovary, 
but the stalk is not as long as in the eggs of Scrobicularia, as described by von Jhering. As 
elsewhere stated, the oyster-egg is not globular when first extruded. It will be readily understood 
that the sexes may be very readily distinguished by these and other marks observed in sections. 
The immature ova are vastly larger thau the spermatozoa, which measure under the ten-thousandth 
of an inch at their largest end. The head of the spermatozoon of both the American and European 
Oyster is globular ; that of the spermatozoon of the Soft Clam (Mya) is ovoidal in form. The tail 
or fiagellum of the spermatic particle is the locomotive organ which lashes back and forth very 
rapidly and propels it through the water and finally brings it into contact with the egg. 

213. NEW METHODS OF DISTINGUISHING THE SEXES AND OF TAKING THE EGGS OF 

THE OYSTER. 1 

Discrimination of the sexes. — One of the first requisites of a practical system of arti- 
ficial fertilization of the eggs of the Oyster is a means which, in the hands of unskilled persons, 
will enable them, without the aid of a microscope, to infallibly distinguish the sexes apart. Such 
a means we now propose to describe. Having tested it practically, and found it possible to 
iustruct persons of ordinary intelligence in a few minutes, we have no hesitation in offering an 
account of the method so as to make it more generally available in the hands of those who may 
be interested in this subject. 

It is premised that the spawn is squeezed from the reproductive glands by the method to be 
described further on. As soon as the spawn is emitted from the generative opening in consequence 
of the pressure exerted upon the gland and the ramifications of its duets, it is drawn up by means 
of a small pipette or medicine dropper, provided with a small collapsible bull* al the upper end 
which is held between the thumb and forefinger. Pressing the bulb between the fingers, then 
immersing the open end of the pipette into the extruded spawn, and then allowing the bulb to 
expand by its own elasticity, it will draw or suck up the spawn which has been pressed out \ en 
neatly; and if one is careful, absolutely nothing but the spawn is picked up. One soon becomes 
very expert in the use of the pipette. 

The next requisite is a shallow glass dish, or even a plain tumbler will answer, into which 
say a half gill of clean sea-water has been poured. Taking up the extruded spawn from the 
opening of the duct it is dropped from the pipette into the clear water. This last simple operation 
enables us to tell without fad to which sex the products belong. If the creamy white mass consists 
of eggs which have been pressed from the generative openings and is dropped into the water, i I will 
at once break up into a granular cloud as the spawn strikes the latter, the granules themselves 



'The observations and experiments discussed in this article were conducted at Saint Jerome's Creek during 
months of July and August, 1882. 



ARTIFICIAL BREEDING OF OYSTERS. 723 

being very distinctly visible, especially.it' the -lass vessel be resting upon a dark ground so as to 
bring the whitish granules into relief. The grannies are nothing more than the ova oreggs of the 
Oyster, and at once indicate thai the individual from which thej were obtained is a female, to 
case the products are male, they break up as thej mingle with the water into a milkj white eloud 
in which no granules are visible to the naked eve. It is also ven importanl to observe thai as the 
milt is stirred in the water it breaks up at firsl into long, fleecy white clouds which resemble very 
strikingly in miniature what are known to meteorologists as cirrus clouds, or, vulgarly, "mare's 
tails' " reminding one of these in the way in which the fine particles of mill give rise to streaks. 
wisps, and fibers as it breaks up in the water, without giving rise to any visible granular appear- 
ance as occurs in the case of the female products, but to an opalescenl or milky aspect. These 
distinctions, once learned, are so palpable that the novice may as infallibly discriminate the sexes 
of the Oyster apart by their aid as can be done by the most skilled biologist with a powerful 
microscope. 

The impregnation op the eggs. — The method formerly used was to first learn the sex of 
a number of adult Oysters with the microscope, then cut out the generative glands with their 
products and cuop up those of different sexes separately iu small dishes with sea-water. This 
system we may now say is barbarous, because it is crude; large numbers of eggs are destroyed 
by crushing, or are injured by the rough usage to which they are subjected, and, besides, there is 
no assurance that the eggs or milt operated with are quite mature. It is also troublesome to free 
the generative gland from fragments of the liver which help to pollute the water in the incubating 
vessels with putrescible organic matter, and thus interfere greatly with the life and healthy devel- 
opment of the embryos. 

By our method the objectionable features of the old plan, as stated above, are overcome. If 
possible, select good-sized Oysters; open them with the greatest possible care so as not to mutilate 
the mantle and soft parts. Carefully insert an oyster-knife between the edges of the valves and 
cut the great adductor muscle as close as possible to the valve which you intend to remove, 
leaving the animal attached to the other valve, which, if possible, should be the left or deepest one. 
The soft parts being firmly fixed or held fast by the great adductor muscle to the left valve 
prevents the animal from slipping under the end of the pipette, held flatwise, as it is gently and 
firmly stroked over the generative gland and ducts to force out the generative products. 

To prepare the animals to take the spawn from them, after opening, the following precautions 
are to be observed : Note that the reproductive gland in great part envelopes the visceral mass, 
and extends from the heart space, just in front of the great adductor, to within a half inch or so of 
the head or mouth end of the animal, which lies next to the hinge. Note also that both sides of 
the visceral mass which incloses the stomach, liver, and intestine are enveloped on either side by 
a membrane which also lies just next the shell and is garnished by a fringe of purplish; sensitive 
tentacles along its entire border except at the head end where the mantle of the left side passes 
into and is continuous with that of the right side of the animal. The ventral or lowermost side of 
the animal, anatomically speaking, is marked by the four closely corrugated gill plates or pouches, 
which are preceded in front by the four palps or lips, but both the gills and palps depend 
downward between the lower borders of the mantle of the right and left sides. Note, too, that 
if the mantle is carefully cut and thrown back on the exposed side of the animal between the 
ivpper edges of the gills and the lower edge of the cut or exposed end of the great adductor 
muscle, the lower and hinder blunted end of the visceral mass will be exposed to view. It is on 
either side of this blunted end of the visceral mass between the upper edge of the gills and lower 
side of the great muscle that the reproductive glands open almost exactly below the great adductor. 



724 NATURAL HISTORY OF AQUATIC ANIMALS. 

From these openings we. will afterwards fiud, if the animal is sexually mature and the operation is 
properly conducted, that the spawn will be forced out in a vermicular, creamy white stream. But 
in order to fully expose the reproductive organ we should carefully continue to sever the mantle 
of one side with a sharp penknife, or small scissors, some distance forward of the great muscle 
towards the head, cutting through the mantle just above the upper borders of the gills and following 
a cavity which lies between the latter and the lower border of the visceral mass. A little 
experience will teach one how far it is necessary to carry this incision of the mantle. For some 
distance in front of the heart space the mantle is free or detached from the visceral mass and 
reproductive organ which lies immediately beneath, and this enables one, if the last described 
incision has been properly made, to almost completely expose the one side of the visceral mass 
and the richly tinted, yellowish- white reproductive gland which constitutes its superficial portion. 
The opening of the gland and its superficial ramifying ducts being laid bare ou the exposed side 
of the animal we are ready to press out the spawn on that side. Before beginning this, however, 
it is important to observe that the principal duct passes down just along the edge of the visceral 
mass where the latter bounds the heart space, in which the heart may be observed to slowly 
pulsate, and that this great duct ends somewhere on the surface of the ventral blunted end of the 
visceral mass. To expose the great or main generative duct it may be necessary to cut through 
or remove the pericardial membrane which incloses or covers the heart space on tlie exposed side. 
If the Oyster is sexually mature, the main duct will be observed to be distended with spawn, and 
that, originating from it and branching out over almost the entire surface of the visceral mass, 
there are minor ducts given off, which again and again subdivide. If these are noted, and it is 
observed that they are engorged, giving them the appearance of a simple series of much branched 
great veins filled with creamy white conteuts, it may be certainly presumed that your specimen is 
mature and that spawn may be readily pressed from it. 

The operation of pressing the spawn out of the ducts requires care. The side of the end <>t the 
pipette may be used, being careful not to crush or break open the ducts as you gently and firmly 
stroke the pipette flatwise over the side of the visceral mass backward from the hinge towards 
the heart space and over the great duct at the border of the hitter diagonally downward and 
backward to the opening of the reproductive organ. If this has been properly done it will be 
found that the generative products are being pushed forward by the pipette through the ducts, 
as the pressure will be seen to distend the latter, the contents of the branches flowing into the 
larger and larger trunks until they are forced outward through the main duct and opening below 
the great adductor, where they will pour out in a stream one-sixteenth of an inch or more in diameter 
if the products are perfectly ripe. The sexes may be discriminated as described at the outsit, ami 
it is well to first find a male by the method already given and proceed to express the milt as 
described above into say a gill of sea-water, adding pipetteful after pipetteful until it acquires n 
milky or opalescent white color. As the milt or eggs are pressed out of the opening of the ducts 
they are to be sucked up by the pipette and dropped into the water, the mixture of milt being firsl 
prepared, to which the eggs may be added as they are expressed from the females. The judgment 
of the operator is to be used in mixing the liquids; in practice I find that one male will supply 
enough milt to fertilize the eggs obtained from three or four females, and it does not matter it I lie 
operation takes from twenty to thirty minutes' time, as the male fluid, which it is best to prepare 
first, will retain its vitality for that period. 

It is always desirable to be as careful as possible not to get fragments of other tissues mixed 
with the eggs and milt, and the admixture of dirt of any kind is to lie avoided. To separate 



RATE OF GROWTH OF OSTREA VTRGINIOA. 725 

any such fragments nicely, I find a small strainer of coarse bolting or cheese oloth to be verj 

convenient. 

In the foregoing- description we have described the method of obtaining the spawn only from 
the side of the animal exposed in opening the shell. A little experience will enable one to lift up 
the head end of the animal and throw it back over the great adductor muscle, expose the opening 
of the reproductive organ on the left side, or 'whatever the ease maj be, and also express the 
spawn from that side, thus as effectually obtaining all of the ripe eggs or mill as is possible in the 
process of taking the same from fishes. 

It is remarkable, to note the success attending this method, since almost even egg is perfect 
and uninjured, the percentage of ova which are impregnated is much larger than by the old 
method, reaching, I should say, quite ninety per cent, of all that are taken when the products are 
perfectly ripe. It is also found that the products are not so readily removed by my process it' they 
are not perfectly mature, which is also to a certain extent a safeguard against getting poor or 
immature spawn. In the course of an hour after the products of the two sexes have been mingled 
together it will be found that nearly every egg has assumed a globular form, has extruded a polar 
cell, lost the distinct germinative vesicle and spot in the center, and begun to develop. 

It is noteworthy that our practice as herein described has completely vindicated the state- 
ment made by the distinguished French anatomist and embryologist, M. Lacaze-Duthiers, that 
there is but a single generative opening on each side of the visceral mass of the Oyster, and that, 
as we have stated, it is found to open just below the great adductor muscle. 

We have also discovered, since the foregoing was written, that the use of an excessive amount 
of milt is of no advantage. The water in which the eggs are to be impregnated only requires to 
be rendered sbghtly milky; a very few drops of good milt is sufficient to make the impregnation 
a success. Too much mdt causes the eggs to be covered by too large a number of spermatozoa ; 
thousands more than are required if too much is used. These superfluous spermatozoa simply 
become the cause of a putrescent action which is injurious to the healthy development of the eggs. 
A drop of milt to twenty drops of eggs is quite sufficient. 

Immediately after the ova have been fertilized it is best to put them into clean sea- water at 
once, using water of the same density as that in which the adults grew. If the attempt is made 
to impregnate the eggs in water much denser than that in which the adults lived, it is probable 
that the milt will be killed at once. This singular fact, which was accidentally discovered by 
Colonel McDonald and myself, shows how very careful we should be to take into consideration 
every variation in the conditions affecting a biological experiment. If sufficient water is used no 
trouble will be experienced from the pollution of the water by dangerous micro-organisms which 
are able to destroy the oyster embryos. From fifty to two hundred volumes of fresh, clean water 
may be added to the volume in which the eggs were first fertilized. This may be added gradually 
during the first twenty- four hours, so as to assist aeration and prevent the suffocation of the 
embryos. 

214. RATE OF GROWTH OF OSTREA VIRGINICA. 

Size of the egg. — The egg of the American Oyster, according to Brooks, is approximately 
5-50 inch, being very nearly perfectly spherical after the extrusion of the polar or direction cells 
(Richtungsblaschen of the German embryologists). This accords with what the writer has observed 
in our species, and in the Portuguese Oyster, probably 0. angulata Lam., the size of the egg 
appears to be about the same, judging from specimens of the latter examined by me in March 
last. Judging from the figures and the stated amplifications given in the papers of M. Davaine, 



726 NATURAL HISTORY OF AQUATIC ANIMALS. 

the egg of Ostrea edulis is jhs mcu m diameter. Estimates based on the figures of M. Lacaze- 
Duthiers give dimensions of -^jo inch. These discrepancies I think are probably too great, and 
may be due to imperfect micrometric methods. If they are real it would indicate a specific 
difference of some importance between 0. edulis and 0. virginiea. 

The actual volume of the egg of the American Oyster would accordingly be a little more 
than 2500 0000? cubic inch, a solid so minute that we are unable to frame any adequate con- 
ception <>f its diminutiveness. Under the best conditions, as seen against a dark back-ground, 
it is visible as a grayish-white speck ; almost an optical point. It is from this diminutive spherical 
mass of living matter that the young Oyster is developed. The development of the embryo 
proceeds, as far as I can make out, according to the accounts given by Davaiue, Brooks, Horst, 
and others, similarly to that of other lamelli branch s. To Hatschek 1 we are indebted foMke most 
secure foundation for our future embryological investigations upon this difficult group of mollusks; 
and we must not forget to mention the very important researches of Ray Lankester (Phil. Trans., 
1875), principally upon Pisidium. I have not been able to observe the development of the larval 
Oyster beyond the size attained by it after the complete segmentation of the egg, the develop- 
ment of the shell, the velum, and alimentary tract. In fact, no embryos which I have attempted 
to rear from artificially impregnated eggs have ever lived long after the time when they began 
to take food, which is immediately after they acquire the velum, permanent mouth, and vent, 
and are almost or altogether covered on either side by the very symmetrical larval shells, which 
consist of carbonate of lime laid down in a matrix of conchioline. The isolation of the conchioline 
is readily effected by the use of acetic acid, the acid dissolving out the lime entirely. I find 
that Brooks and Dr. Horst 2 have tried a similar experiment with similar results. The latter 
writer has also been able to watch the development of the naturally impregnated ova of Ostrea 
edulis until a pretty advanced stage was reached. He disagrees with Brooks in his interpretation 
of the gastrula stage, and thinks that the invagination regarded by the American investigator 
as the blastopore must be considered to represent simply the first rudimenl of the shell-gland. 
In assuming this position, from what 1 have been able to gather in the course of my own investi- 
gation of the development of the American species, I think we are bound to accept Dr. Horsfs 
determination of the homology of the shell-gland of the Oyster with that of other lamellibran- 
chiate and cephalophorous mollusks. 

Early stages of development. — The oral invagination, according to Dr. Horst, originates 
on i he opposite or ventral side of the embryo and has no connection with the dorsal pallial 
invagination or shell gland. The early stages of the American and European species, like the 
later ones, appear to present no marked differences, except that the lat ter appears, on the evidence 
of Dr. Horst, Mobius, and others, to carry the ova and embryo in the mantle cavity, from which 
the first named author obtained his material for study, by breaking a hole through the shell near 
the margin, so as to enable him to introduce a pipette into the" pallial chamber. This method of 
getting embryos is impossible in our native species, which lias wholly different breeding habits, as 
is proved by the investigations of Brooks, Wmslow, Rice, and myself. How much further than 
heretofore Messrs. Brooks and Winslow have been enabled to cany the development of our native 
Oyster during the past season ai Beaufort, North Carolina, I have not been able to learn, nor do 1 
know anything more definitely as to how much success has been attained in the artificial produc- 
tion of Ostrea edulis from artificially-impregnated eggs at the hands of Mr. Littlewood, of England, 



' Oeber Emvvickelutigssesohiclite von Teredo. Arbeiten ans item Zool. Inst. Wien., Bd. iii. 

2 Bijdragetotde Kennis van de Ontwikkelingsgeschiedenis vandeOester (Ostrea edulialj.), door Dr. E. Horst. Tijdschr 
d. Ned Dierk. Vereen, Deel, vi, 1882. 



LaEVAL OTSTBBS. 727 

who has claimed that he had succeeded in rearing them to the age of five months, specimens oi 
which it is said were shown at the Fishery Exhibition recently held in Edinburgh. 

Experiments at Saint Jerome's Creek. — Our experiments made al Sainl Jerome's Creel; 
during the past summer gave the most contradictory results, ami the interval of development 
between that of our oldest embryo with its diminutive Pisidium like valves measuring aboul .',, 
iuch in diameter, and that of the embryo when its valves first begin to lose their embryonic form, 
still remains unbridged. The dimensions of the embryo or "fry," as we ma3 more properlj call it 
when it becomes fixed, are between a 1 ,,- and „V iuch according as the measurement is made longi- 
tudinally or transversely. The difference in magnitude between the oldest artificially incubated 
fry seen by me and that of the youngest fixed embryos which 1 collected is very small, amounting 
only to jjrfc) inch, or a little more than -^ iuch. To determine the relative volumes of these 
stages, and consequently the amount of food which has been taken in and converted into the 
structure of the more advanced stage in addition to the original bulk of the egg, we need onlj 
take the cubes of their respective diameters and compare them. Taking the diameter of the egg, 
or j-^jj inch, as the diameter of the most advanced embryo seen by me, which we will consider 
unity, and comparing it with „V inch, or the transverse diameter of the newly fixed fry, we find, 
after having reduced the last quantity to its simplest form as compared with 1 , or the diameter of 
the egg, that we have 5.1+. The diameters then of the first and last embryonic or truly larval 
stages are to each other as 1 is to 5.1 + , and consequently their volumes will be to each other as 
the cubes of these numbers, or as 1 is to 132.651 + . The difference between these two quantities, 
or 131.651+ times 1, will give us approximately the amount of food material which has been taken 
up by the embryo in passing from the condition when it was first able to feed until it fixed itself. 
showing that the process of growth has been going on vigorously in order to augment tiie volume 
of the young creature at the enormous rate indicated by our figures. We have, however, been 
dealing not with absolute but with relative or compared volumes only; if the egg contains 
25 0000000 cubic inch of protoplasmic matter approximately, the newly-fixed fry, which we will 
assume to be globular, and contains, as shown above, over 132 times as much material, the 
absolute bulk of the latter will be 25000000? cubic inch multiplied by 132, or bsttoooooo cubic 
inch, which, in its simplest form, is therefore 1 ' 93 .^ 076 cubic inch, or the absolute volume of the 
newly fixed fry. Mnety cubed, or 729,000 young Oysters could therefore be contained in a cubic 
inch of space, if taken at the stage at which they begin to be transformed into spat. This large 
number is, of course, small when compared with 125,000,000, the number of eggs which might be 
contained by the same extent of space. 

The larval character of the young Oyster. — The proof of the larval character of 
the youngest fixed stage of the Oyster rests upon the three following well-ascertained facts : 
1st. The perfect symmetry and great convexity of the valves; 2d. The entirely different shape 
of the shell as compared with those of the spat and adult; 3d. Its wholly different micro- 
scopic structure when compared with the later and full-grown stages. The form of the shell, at 
the time the animal is about to begin to develop the spat shell, is suborbicular, very thin, ven- 
tricose, resembling in many respects the shell of Cyclas or Pisidium, having the symmetry of 
those genera, with umbones of about the same form and prominence. These features mark the 
.'larval shell of the Oyster so unmistakably that its valves may always be very readily recognized 
•at the tips of the valves of spat under a year old. The larval valves lie on the tips of the valves 
'of the spat like small hemispherical caps, but can usually not be found after the young Oyster 
enters upon its second year, as its umbones, together with the larval shells which surmount them, 



728 NATURAL HISTORY OF AQUATIC ANIMALS. 

have been eroded by the action of the carbonic dioxide in solution in the sea-water. The 
presence of the larval shells in an unimpaired condition on the umbones of the valves of Oysters 
is therefore an indication that such specimens are young, probably under a year old. 

The third character, alluded to above, which distinguishes the larval shell of the Oyster is 
the perfect homogeneity of the calcareous matter. Unlike the valves of the spat or translucid 
flakes from the shell of the adult, they exhibit no prismatic arrangement of the calcic carbonate 
in a matrix of conchioline. In the valves of the adult and spat, on the other hand, the calcic 
carbonate tends to assume a prismatic arrangement vertical or at right angles to the plane of 
the length and breadth of the shell. This distinction is so marked that in very young individuals 
which have only lately become fixed one may very readily determine with the aid of the micro- 
scope the line of demarkation along which the formation of the larval shell ceased and where the 
prismatic calcareous structure of the valves of the spat began to be developed. 

Characters of the laeval shell. — The only characters of structure which the larval 
shell has in common with that of the spat and adult are the lines of growth visible in all three. 
This shows that the valves grow in extent at all stages by the addition of lime to the edges of 
the valves, each layer of mineral matter aud organic matrix extending over successively greater 
and greater areas, as in the growth of the shells of mollusks in general, the umbones being 
the points from which the valves grow in an eccentric manner in consequence of the gradually 
increasing extent of the mantle — the shell-secreting organ — as the growth of the animal 
proceeds. Having clearly defined the nature of the larval shell of the Oyster, up to the time 
when it is ready to begin to build or secrete the shell of the spat, we may next discuss the 
character of the transition from the one to the other. 

The transition is apparently an abrupt one. The excessive convexity of the valves of the fry 
contrast strongly with the almost flat lower valve and feebly convex upper one of the spat. At 
(lie free edges of the larval shells where they pass directly into the structure of the valves of the 
spat there is a marked offset or angle marking very distinctly the difference of convexity be! ween 
the two stages of shell development. 

Food of the young Oyster. — As already remarked, I have seen food in the intestine 
of the young Oyster on the second day of development, but how long it may take before the 
young embryo of this stage of growth shall have taken and appropriated one hundred and 
thirty-two times its own volume of food material, I am not able to say. This it must do 
before it can have attained to the size of the larva which is transformed into spat. The food 
is propelled through the alimentary canal by the action of innumerable vibratory filaments 
which clothe the inside of the throat, stomach, and intestine as in the adult; the intestine, 
stomach, and liver are not, however, as complex as in the full-grown animal. 

Of the method of fixation 1 have as yet learned nothing of value. That this is accomplished 
by some sort of byssus 1 have no doubt. The fact that it is the left valve which is always the 
lowermosi aud attached one would indicate that the method of fixation was not capricious or 
haphazard in its nature. 

I would infer from what we learn from the study of other animals that it may require quite a 
week before an embryo reaches the dimensions of one-eightieth of an inch, but we have no data 
upon which to base any conclusions of value. Of the later stage of development we know some- 
thing definitely. The main fact which we have so far decided is the size of the larval shell. 

Rate of growth. — After fixation the growth of spat is very rapid, as may be inferred 
from the fact that I have found spat upon collectors which had not been placed in position 



FOOD OP TEE OYSTER. 729 

more than a week to ten days, upon which 1 detected spat one-fourth of an inch across. In 
other cases the following were the observed dimensions: On a collector which had been placed 

near a bed of spawning Oysters for twenty days L obtained a apecii of spat seven-sixteenths 

of an inch across; from another collector immersed for forty-four days 1 obtained specimens 
thirteen-sixteenths of an inch in diameter; from another out forty-eight days a specimen 
measuring about one inch. Another set of collectors which had been out for seventy-nine days 
had spat attached which measured one and three-fourths inches across. Some still larger spat 
collected by me was not over eighty-two days old, ami measured nearly bwo inches in length 
from the hinge to the distal margin of the valves. Still larger specimens have been observed 
by the writer, which bore every evidence of having affixed themselves during the same 
season. 

If we contrast the above measurements with those given by Mobius of the spat of 0. edulis 
of known age, I conclude that the American Oyster grows three or four times as rapidlj as the 
former. For instance, Mobius figures a European Oyster twelve to fifteen months old, which 
measures only one and one-fourth inches in diameter. Contrasting this with the size of the 
American at seventy-nine to eighty-two days old, and measuring from one and three-fourths to 
nearly two inches in diameter, we see how greatly our species surpasses that of Europe in vigor 
and rapidity of growth. 

Of the rate of growth beyond the ages given above I have only a few data, based on the spat 
which was caught on collectors put out in Saint Jerome's Creek in July and August, 1880. In the 
following autumn the collectors which had been put out into the creek were taken up and the spat 
removed from them. This was then put into a box, through which the water could circulate 
freely, and put back into the creek, in order that we might be enabled to learn how much growth 
these young Oysters would make during the winter and next season. I did not have an opportu- 
nity to examine them, however, until the 10th of July, 1882. From the time of their fixation in 
July and August, 1880, to the time when I made my last examination of these specimens, a 
period of about twenty-three months had accordingly elapsed. One of the largest specimens 
examined by me measured three and three eighths inches in length and two and fivo-cighths 
inches in width. Another smaller specimen measured two and a half inches long and two 
and a quarter inches in width. They were about the size of Oysters available for planting, and I 
have no doubt that in the course of two or three years more, if placed under favorable conditions, 
they would reach a marketable size. The inference, therefore, is that it takes at least four to live 
years for an Oyster to grow large enough, starting from the egg, to be available for market. 

In order that an Oyster may grow to attain the great size of certain single individuals which 
I have seen, it may take even ten years. I should think it would take at least that length of time 
for an Oyster to grow until its valves would measure nine inches in length, a few of which I have 
seen of this enormous size. These, it must be remembered, were not "Raccoon Oysters" or "Cat's- 
tongues," as the narrow, elongate individuals are called which grow so densely crowded together 
upon the banks as to be abnormally lengthened. Under favorable conditions, I do not think 
it improbable that an Oyster may live to the age of twenty years, attaining corresponding 
dimensions. 

215. THE FOOD OF THE OYSTER. 

Observations at Saint Jerome's Ceeek. — The following extracts, taken mainly from 
my report for 1880 to the Fish Commissioner of Maryland, will give some idea of the kinds of 
organisms usually encountered on oyster banks and beds. These observations were made at 



730 NATURAL HISTORY OF AQUATIC ANIMALS. 

Saint Jerome's Creek, a few iniles north of tbe mouth of the Potomac, during the months of July. 
August, September, and October: 

"The food of this mollusk, as is well known, consists entirely of microscopic beiugs and 
fragments of organic matter, which are carried by currents from the palps and gills, which have 
been already described, to the large mouth of the animal at the hinge end of the shell. The inside 
of the gullet and stomach, like some other parts of the body, are covered with cilia, so that food 
once fairly in the mouth will be carried by their action down to the cavity of the stomach, where 
it is carried into the folds and deep pouches in its walls, and even into the openings of the bile 
ducts, to undergo digestion or solution, so as to be fitted in its passage through the intestine to 
be taken into the circulation, and finally disposed of in building up the structures of the body. 

"Along with the food which is taken, a very large amount of indigestible dirt, or inorganic 
matter, is carried in, which, in a great measure, fills up the intestine, together with the refuse or 
waste from the body. This material, when examined, reveals the fact that the Oyster subsists 
largely on diatoms, a low type of moving plants which swim about in the water, incased in minute 
sandstone cases, or boxes, of the most delicate beauty of workmanship. These, when found iu 
the intestine, have usually had their living contents dissolved out by the action of the digestive 
juices of the stomach. I have found in our own species of Oyster the shells of three different 
genera of diatoms, viz: Campylodiscus, Coscinodiscux, and Navieula. The first is a singularly bent 
form; the second is discoidal; and the last boat-shaped, and all are beautifully marked. Of 
these three types, I saw a number of species, especially of the latter, but as I was uot an authority 
upon the systematic history of any of them 1 had to neglect the determination of the species. No 
doubt many more forms are taken as food by the Oyster, since 1 saw other forms iu which the 
living matter inside the siliceous cases was brown, the same as in most of the preceding forms 
which I have indicated. Some of these brown forms were so plentiful as to color a considerable 
surface whereon they grew of the same tint as themselves. 

"Besides the diatoms and the spores of algae, tbe larvae or young of many animals, such as 
sponges, bryozoa, hydroids, worms, mollusks, are small enough to be taken in as aliment by 
tin- Oyster, though their bodies in most cases being soft and without a skeleton, it is impossible 
to hud any traces, either iu the stomach or intestine, of their remains, to indicate that they have 
formed a part of the bill of fare of the animal. What, however, demonstrates that such small 
larval organisms do help to feed the Oyster is the fact that at the heads of tin' small inlets oi 
creeks along the Chesapeake, where the water is but little affected by the tides and is somewhat 
brackish and inclined t<> be stagnant, there always appears to be a relatively greater development 
of a somewhat characteristic surface or shallow water fauna of minute forms. 

"In Saint Jerome's Creek the microscopic fauna of its headwaters is entirely different from 
that of the body of the creek; two minute forms inhabit in vast numbers the former, while I 
sought in vain for them in the more open and changeable waters of the main body of the inlet, 
which arc brought into active movement twice a day by the action of the tides. One of these 
forms, an iufusorian, 1 one twenty-fifth of an inch in length, was found covering every available 
surface of attachment, so that countless multitudes of the naked young would be swimming about 
in the water previous to building the curious spiral tubes which they inhabit — admirably fitted in 
this state as food tor the Oyster. Besides the type referred to, there were a number of other 
infusorians, which in their so-called swarming stages of development would become available 
as Oyster food. Of such types I noticed four different species, either belonging or very nearly 



1 On the occurrence of Freia producta. Wright, iu the Chesapeake Bay.— Am. Naturalist, 1880, pp. 810, 811. 



LOCATION OF OYSTER BEDS. 73] 

related to the semis Oothurnia; all of the forms buill tubes for themselves, l also noticed several 
forms of bell animalcules, the swarmers of which would become available as food for the Oysters 
lying in the vicinity. 

"The diatoms did not seem tome to be more abundant in the headwaters ilian in I lie open creek. 
There was one moss animal of remarkable character, which 1 found in the headwaters only. This 
creature was very abundant, and no doubt its embryos, like those of the infusoria referred to, were 
available as food. 

"Of free-swimming infusorians, I noticed a number of genera; one especially attracted my 
attention from its snake like appearance and singularly rapid contort ions ; it had a tuft of vibrating 
hairs or cilia at the head end in close relation with the mouth. Another more abundant type was 
the curious genus Euplotes, with a thick shell inclosing the soft protoplasm of the body ; the latter 
was of an oval form, flat beneath and rounded on the back, so that the resemblance when the 
large foot-like cilia were in motion, carrying the animal about, was strikingly like a very minute 
tortoise, the resemblance being heightened when the animal was viewed from the side, 

"Rod-like algffi of minute size, the larva? of Crustacea, especially the vast numbers of extremely 
small larval Gopepoda, must enter as a perceptible factor into the food supply of the Oyster. 

" There is no doubt but that the comparatively quiescent condition of the headwaters of these 
inlets and creeks, available as oyster-planting grounds, are more favorable to the propagation of 
minute life than the open bay or creeks, where the temperature is lower and less constant. Prac- 
tically, this is found to be true, for oystermen seem to be generally agreed that Oysters ' fatten' 
more rapidly, that is, feed more liberally in the headwaters — blind extremities of the creeks — than 
elsewhere. This notion of the oystermen is in agreement with my own observations during the past 
year. Oystermen also assert that Oysters 'fatten' more rapidly in shallow waters than in deep 
ones, a point upon which I made but few observations ; but such as I did make tended to confirm 
such an opinion. In illustration I may contrast the condition of the Oysters in the pond leased by 
the commission at Saint Jerome's and those dredged off Point Lookout, in twenty or thirty feet of 
water, on the 3d day of October, 1S80. The Oysters in the pond, by the middle or end of September, 
were in good condition as to flesh, and marketable, while those from deeper water off Point Lookout, 
and but little later in the season, were still extremely poor, thin, and watery, and utterly unfit for 
market. These differences in condition, it seems to me, are to be attributed in a great measure to 
differences of temperature and the abundance of food, but mainly to the latter." 

These observations give us some hints regarding the advantages arising from the cultiva- 
tion of Oysters in more or less stagnant water, in which, as in the French parks or elaires, an 
abundance of microscopic life would be generated in consequence of a nearly uniform temperature, 
higher in the early autumn months at least than the waters of the open sea, where cold currents 
also would tend to make it still less uniform and thus interfere with the generation of the minute 
food of the Oyster. In other words, it would appear that the effect of the French method is to 
furnish the best conditions for the rapid and constant propagation of an immense amount of 
microscopic food well adapted to nourish the Oyster. That unlike Oysters exposed to a rapid flow 
of water on a bottom barren of life they grow and quickly come into a salable condition. 

Situations best adapted foe oyster cttlttjee. — In this country narrow coves and 
inlets with comparatively shallow water appear to furnish the best conditions for the nutrition 
and growth of Oysters ; and according to my own experience these are the places where we act- 
ually find minute animal and vegetable life in the greatest abundance, and, as might have 
been expected, the Oysters planted in such situations appear to be in good condition early in 
the autumn, long before those which are found in deeper and more active water, where their 



732 NATUEAL HISTOEY OF AQUATIC ANIMALS. 

food has less chance to multiply. If the French mode applies successfully to an inferior species, j 
ours, which grows so much more rapidly, ought to derive a proportionally greater benefit from 
being treated in the same manner. However, before we are ready to deal with the material ; 
on which the Oyster feeds, we desire a more perfect acquaintance with the microscopic life 
which grows upon oyster-beds and swims about in the adjacent waters. From the fact that 
the lower forms of life in fresh water often appear in great abundance one year, while in the 
.next, from some unexplained cause, none of the same species will be found in the same situation, 
we may conclude that similar seasonal variations occur in the phases of the microscopic life of 
a given oyster-bed and its vicinity. 

Influences of environment. — Such yearly variations in the abundance of microscopic 
life are probably the causes of the variable condition of the Oysters taken from the same beds 
during the same season of different years. Violent or sudden changes of temperature are prob- 
ably often the cause of the destruction of a great amount of the minute life upon which the Oyster 
feeds. Backward and stormy seasons doubtless also affect the abundance of the microscopic life 
of the sea. All of these questions have, however, as yet been scarcely touched, and, judging from 
the disposition of many of our students of zoology to be content merely with a description of new 
species and the compilation of lists, instead of also entering into investigations of the life-histories, 
the relative abundance of individuals, and the influence of surrounding conditions upon the 
forms they study, it will take some time yet before we get the information so much desired. 
When we arrive at this knowledge we will know why it is that Oysters taken from a certain bed 
are in good condition for a season or two and then for one or more years are found to be watery and 
of poor quality, as well as why it is that the Oysters of certain beds, which for years have had a 
high reputation for their fine qualities, are suddenly found to be more or less green in the beard, 
as I have been informed is now the case with the Oysters of Lynn Haven Bay, Virginia. 

As to the influence of brackish water in improving the condition of Oysters, let me observe 
here that those who hold to that opinion appear to forget to bear in mind that brackish-water beds 
are often in the case just described ; that lying in shallow, relatively quiet water, an abundance 
of food is generated which is rapidly consumed by the animals, quickly bringing the latter into 
condition, the brackish state of the water getting the credit of the result. 

"In a paper published in the report to the British Government on oyster-culture in Ireland, 
in 1870, Prof. W. K. Sulbvan, of Dublin, remarked that independently of the mechanical constitu- 
tion of the shore and littoral sea-bottom, *'. e., deposition of sediment, the currents, the temperature, 
etc., the nature of the soil produces a marked influence upon the food of the plants and sedentary 
animals that inhabit the locality, as well as upon the association of species. Especially is it the 
case with Oysters, that the soil exerts so much influence on the shape, size, color, brittleness of 
shell, and flavor of the meat, that an experienced person can tell with great certainty where any 
particular specimen was grown. 1 . . . Were we able to determine the specific qualities of 
i be soil which produce those differences in the qualities of Oysters, it would be an important step 
in their cultivation. Again, soils favorable for the reproduction of the Oyster are not always 
equally favorable for their subsequent development; and, again, there are many places where 
Oysters thrive but where they cannot breed. This problem of the specific influence of the soil is, 
however, a very difficult and complicated one. First, because it is almost impossible to separate 
the specific action of the soil from that of the other causes enumerated ; and next, because, though 
much has been written on the subject of Oysters, I do not know of any systematic series of experJ 

1 E. Ingersoll : Report on Oyster Industry, Tenth Census. 



PROTOZOANS OF SAlVf JEROME'S CREEK. 733 

meiits carried out upon different soils, and for a sufficient length of time to enable accidental 
causes to be eliminated, which could afford a clue to the determination of the relative importance 
of the action of the several causes above enumerated at the different stages of development of the 
Oyster. ... I believe the character and abundance of Diatomacea and Rhizopoda, and other 
microscopic animals, in Oyster- grounds, is of primary importance in connection with Oyster 
cultivation. The green color of the Colchester and Marennes Oyster shows how much the quality 
may be affected by such organisms. It is probable that the action or influence of the soil of Oyster- 
grounds upon the Oyster, at the various stages of its growth, depends mainly upon the nature and 
comparative abundance of the Diatomacea, Rhizopoda, Infusoria, and other microscopical organisms 
which inhabit the ground. I have accordingly always noted where the mud appeared to be rich in 
Diatomacea, Foraminifera, and other microscopic organisms. A thorough a study of a few differently- 
situated Oyster-grounds, exhibiting well-marked differences in the character of the Oyster from 
this point of view, by a competent microscopist, acquainted with the classes of plants and animals 
just mentioned, would be of great scientific interest and practical importance." 

Protozoans of Saint Jerome's Creek.— The Protozoan fauna of Saint Jerome's Creek 
presents considerable variety; several species of test-building Cothumiw were noticed, one 
Yaginicola, three species of Yorticella or bell-animalcules, free-swimming Uuplotes, Nassula ; of 
the latter type an exceedingly elongate form was noticed, with a body almost as slender as a 
thread-worm. Monads were noted sometimes in profusion, though some of these may have been 
tne spores of algse. Amoeboid forms were very few, and the only one which was frequently 
noticed was a form so nearly like Actinophrys sol that I would pronounce it the same. 

The Freia producta Wright was most common ; this creature is related to the fresh- water 
trumpet animalcules, and is one of the most beautiful Protozoans I have ever seen. I reproduce 
here, with some changes, my description of the Chesapeake form from the "American Naturalist" 
for November, 1880 : 

" The tubes in which the animalcule resides are formed of a narrow transparent ribbon of 
horny consistency, wound into a spiral and terminating in a trumpet shaped extremity, from which 
the odd peristome of the inhabitant protrudes. The basal or attached end is usually bent at an 
angle to the tube and bears a striking resemblance to the foot end of a stocking resting upon the 
sole. This portion is not composed, like the tube, of a spiral ribbon, but is simply a thin-walled 
sac, from the open end of which the ribbon takes its rise, but it is composed of the same kind of 
material. Many of the tubes show a trumpet-like rim projecting from the sides of the former, a 
little above the middle, and of the same form as the terminal rim, showing that this, like the form 
described by Mr. Wright from British waters, may stop building its tube for a time and then 
recommence. 

"The adult animal, tube and all, when fully extended, will measure one twenty-fifth of an 
inch in length. It is of the same color as Stentor cceruleus, or bottle-green, but has the power of 
elongating and twisting itself as greatly as 8. rceseli. The peristome is quite unlike that of Freia 
ampulla and bears a strong likeness to the blades of a pair of obstetrical forceps. The blades are 
deeply grooved, forming a deep ciliated demi-canal with parallel sides, and at the junction of their 
bases lies the spacious, twisted, and spirally ciliated pharynx, which is bounded dorsally and 
ventrally by the promineut folds which unite on either side with the long, curved lobes of the 
peristome. There is a small basal disc as in Stentor, and the ectosarc is traversed as in that genus 
by parallel granular bands, regarded as muscular fibers by some writers. The usual food-balls 
and vacuoles are present, and I was enabled to define sharply the endosarc from the ectosarc, 



734 NATURAL HISTORY OF AQUATIC ANIMALS. 

and clearly see the nucleus. The tube or ribbon-secreting organ described by Wright I was unable 
to discover. 

" Wheu fully extended the basal portion of the animal becomes attenuated to a thin bluish 
filament, which widens towards the peristome, where the body is over half as thick as the inside 
diameter of the tube. When fully retracted and resting, the animal resembles in its oblong shape 
a retracted and resting Stentor, and measures about -^ as long as when fully extended. The 
ribbon which forms the tube makes from four to twenty-four turns in specimens of different ages." 

This organism I siuce find to be an inhabitant of the bay also, but is not so abundant as in 
the creek. Small mica collectors fixed to floating corks in the hatching jars and aquaria used 
during the past season were found to afford a nidus for Freia as well as Zoothamnium, the latter 
multiplying at a most astonishing rate in a very few days. Under similar conditions, amoeba?, 
apparently A.proteus, multiplied at a suprising rate; this was the case, too, with a small brown 
diatom which would coat in three or four days the sides of the glass vessels with a thin brownish 
film composed of countless myriads of individuals of the one species. The temperature of the 
bay-water used in the aquaria at this time would range from 76° F. to 89° F. The Vorticellidw 
also soon attach themselves, and next to the hypotrichous infusorians found in the locality are the 
most important animalcular forms found in the Chesapeake. At the mouth of the Cherrystone 
River I last year found I/icnophora cohnii, in great abundance ectoparasitie upon an unidentified 
hydroid. The heliozoon, Actinophrys sol, is found in the bay and Saint Jerome's Creek, and 1 think 
it capable of swallowing dead or enfeebled Oyster eggs and embryos. 

Mutual relations between the Oyster and its prey. — Mobius calls an Oyster- 
bank a Bioccenosis or interdependent community of life. The many species of animals found 
on the banks and beds are no doubt more or less mutually dependent upon each other for 
subsistence, but this is perhaps not any more true of Oyster-banks than it is of terrestrial 
faunae. There are no doubt vast numbers of floating embryos of Oysters eaten by other 
animals growing on the beds which bring their food supply to themselves by means of 
currents produced by ciliary motion. On the other hand, there are no doubt vast numbers of the 
minute swimming embryos of these, drawn in and swallowed by the Oyster, which may, indeed, 
for aught we know, in this way swallow many of its own young, for the current produced by the 
Oyster by means of the cilia clothing its gills is by no means a feeble one, though it is exceeded 
in power by the current flowing into and out of the siphons of Mya. In the latter I have frequently, 
upon opening the animal, found several Copepoda plainly visible to the naked eye swimming 
about in the water in the inferior mantle cavity, which had evidently been drawn in bj the inward 
current. It is plain in this case that very mild means may become effective as prehensile and 
destructive agents, so as to bring remotely related types into intimate vital relations. 

Though an animal may be apparently Invulnerable on account of the effectiveness of its 
covering, it cannot emancipate itself from the abiding struggle it has to make to obtain food, no 
matter how passively it may appear to conduct itself. The Oyster has such a character, yet it has 
been apparent from what has been observed before, that it is entirely dependent for a vigorous 
existence upon the favorableness of surrounding conditions. The beds and banks in a true sense 
are interdependent communities, whose vigor may no doubt be impaired by the removal of a single 
one of its members. Suppose we should take away the algae, diatoms. Oyster-crabs, vibriones, 
bacteria, infusoria, in fact all the minute life; we should greatly impair if not destroy the vitality 
of the beds. While it is true that many of even the smallest forms may destroy food which 
should properly be consumed by the Oyster, that were i( not for the presence of these same small 
forms some destructive element might attain such a development as to be more injurious still. 



CAUSE OF THE GREEN COLOK OF THE OYSTER, 735 

There is therefore no doubt but that a delicate balance of power is maintained by these rivals 
which is best for the health of the community. The stability of permanent oyster beds, it must 
be remembered, furnishes the right conditions for the survival of many types. It is a place where 
they find both a home aud plenty of food. It is the very favorableness ottered l>.\ these places 
which tends to induce them to congregate and multiply, and it becomes a serious question whether 
the artificial establishment of banks will not in time cause the proper types to congregate and 
multiply so as to afford the needed food supply for the Oysters. That destructive members of the 
community may also be attracted is admitted, but if the beds are established in shallow waters, as 
I have previously suggested, the destruction of such unwelcome intruders may be very readily 
effected. " Drills " and boring-sponges are naturally to be thought of as rypes which should be 
destroyed, while diatoms, infusoria, small polyps, bryozoa, minute algae, etc., are to be favored in 
every way. Those forms again which the oyster-culturist knows are only there for the purpose 
of getting a good living with little trouble to themselves ought to be destroyed. 

It might be an advantage to introduce certain desirable forms onto a bank, which might be 
supposed to be useful as a food supply. Infusoria aud diatoms not previously existing might be 
introduced in this way ; this, I think, would be especially easy in the case of the former where 
the type was one which is fixed during its adult life. 



216. ON THE CAUSE OF THE GREEN COLOR OF THE OYSTER. 

Experiments at Washington and Philadelphia. — I have frequently read accounts of 
Oysters which had become green-fleshed in certain localities, and it has also been asserted that 
competent chemists had discovered poisonous green substances of metallic origin in such speci- 
mens. Tests made at the Smithsonian Institution by Professor Endlich in 1879 failed to disclose 
anything poisonous in some green Oysters which had excited the suspicion of the Board of Health 
of the city of Washington. This investigator, it is desirable to state, resorted to every test known 
to him in order to discover if anything poisonous was present, and failing to discover any harmful 
substance concluded that the color must be due to some inert material. In order to see if the color 
was due to the presence of some green compound of copper, Prof. H. C. Lewis, of the Academy of 
Natural Sciences of Philadelphia, kindly made some delicate tests for me, using small dried frag- 
ments of an Oyster very deeply tinged with green in various regions, especially in the liver, con- 
nective tissue, and mantle. The fragments were burned in a bead of microcosmic salt and chloride 
of sodium on a clean platinum wire in a gas flame ; this test did not give the characteristic sky- 
blue flame which should have been developed had there been the minutest trace of copper present. 

It is therefore clear that the substance, whatever it may be, is not a corrosive metallic poison 
derived from copper, which if present would almost undoubtedly be detected by a peculiar acrid 
metallic taste, which would be experienced when one ate such Oysters. In making some practical 
tests as to the relative qualities of such Oysters as compared with white-fleshed ones, oppor- 
tunities for which were kindly furnished me by Mr. J. M. Carley, of Fulton Market, I faded to 
detect the slightest, difference of flavor. Such also is Professor Leidy's verdict, who informs 
me that he made a similar experiment, and a restaurateur, with whom I discussed the matter, 
declared that he was in the habit of selecting them for his own eating, preferring their flavor to 
that of the white Oysters. 

Variations in color. — If it be objected that the green color indicates an unhealthful 
condition of the animal, it may be stated that other color variations of the flesh have fallen 



736 NATURAL HISTOEY OF AQUATIC ANIMALS. 

under my observation recently. What is now alluded to is the yellowish, verging toward 
a reddish cast, which is sometimes noticed in the gills and mantle of both the American and 
European species. This, in all probability, like the green color, is due. to the reddish-brown 
matter which is contained in much of the diatomaceous food of the animal. 

Mr. J. M. Carley has also called my attention to these variations, and was inclined to attribute 
them to the soil in the vicinity of the beds. But if the classical writers are to be trusted, to the 
green, yellow, and white fleshed sorts we must add red, tawny, and black fleshed ones. Pliny 
tells us of red Oysters found iu Spain, of others of a tawny hue in Illyricum, and of black 
ones at Circeii, the latter being, he says, black both in meat andshell. Horace ami other writers 
awarded these the palm of excellence. — (O'Shaughnessy.) However, the black appearance may 
only have been due to an abundance of the natural purple pigment in the mantles of the animal, 
which varies very much in different forms; some, judging from the dark purple color of the whole 
inside of the shell, must have the whole of the mantle of the same tint. The amount of color in 
the mantle, especially at its border, varies in local varieties of both the American and European 
species, as may often be noticed. 

Sometimes almost the whole of the outside surface of the mantle is charged with dark purple 
pigment cells. That copper is not usually the cause of the green color of ( >ysters I also have the 
additional testimony of Prof. W. K. Sullivan, of Dublin, who says: 

"As the green color of the mantle of Oysters from certain localities just referred to is 
commonly attributed to copper, and as such Oysters are consequently believed very generally to 
be poisonous, and their value therefore greatly depreciated, 1 made the most careful search for 
traces of that metal iu the muds which I had received from grounds known to produce green 
bearded Oysters. Oysters and other mollusca placed in solutions containing copper and other 
metals absorb them and retain them in their tissues. I have had two or three opportunities of 
examining Oysters which had assimilated copper, owing to mine water containing it being allowed 
to flow iuto estuaries at places close to oyster bed>. In every case the copper was found in the 
body only of the Oyster, which it colored bluishg-reen, and not in the mantle or beard, which was 
not green. In the green-bearded Oysters which 1 have had an opportunity of examining, the body- 
was not green, and no trace oi copper could be detected in any part of the animal. The color, 
too, was not the same as that of the true copper Oysters, but rather that which would result from 
the deposition of chlorophyl or other similar chloroid vegetable body in the cells." 

The American consumer, however, need not, be alarmed about the presence of copper in our 
species, as there are no beds on our eastern coast into which the washings from mines ever flow, 
as we have no workable deposits of copper near auy of our beds, as in Cornwall, England. Besides, 
I am inclined to doubt the statement of Professor Sullivan that Oysters or other mollusks can 
absorb copper salts until their tissues are •• colored bluish green." Every competent histologist 
knows how very readily organisms are killed by the action of inorganic acids and salts, several of 
which are constantly used by biologists in fixing histological characters. Liebig, in his "Animal 
Chemistry," long ago pointed out that the oxides and metallic compounds of antimony, arsenic, 
copper, and lead had a very remarkable affinity tor protoplasm, producing its immediate death. 
In consequence, he suggested a very high chemical equivalency for living matter. This has since 
been confirmed by the studies of Loew and Pokorny, who found that silver uitrate would produce 
a reaction with protoplasm if diluted to the extent of one part to a million of water. 

Probable cause of the green color. — It is highly probable that the green color of the 
Oyster is due to the absorption from its food of a harmless vegetable pigment. In this country 
green-bearded Oysters occur at Lynn Haven Bay, Hungers and York Rivers, Virginia, on the 



OBSERVATIONS OF GAILLOE AND JOHNSTON. 737 

coast of New Jersey, in New York Bay, and Lou-- Island Sound. I have seen specimens from a 
number of these localities, and also tasted them both raw and cooked without being able to detect 
any disagreeable or apparently harmful flavor. 

Diatoms and green alga? occur in great abundance in the stomach of t he Oj ster, especially the 
former. The intestine is sometimes packed with countless numbers of bhe emptj I'nisi ules or tests 
of diatoms, mixed with dark, muddy ooze or sediment and very line particles of sand or quartz. 
It has been objected that the green color could not be derived from diatoms, because tln.se organ- 
isms are, as a rule, apparently browu rather than green. Tins objection I find to be based upon 
a. misapprehension of the structure of the Diatomaeew, as may be gathered from the following 
general statement taken from Sachs' "Text Book of Botany," one of the latest and highest 
authorities. On page 222 he says: "The diatoms are the only algoe except the Conjugates in w liieh 
the chlorophyl occurs in the form of disks aud bands, but iu some forms it is also found in grains, 
and the green coloring matter is concealed, like the chlorophyl grains in Fucacece, by a buff-colored 
substance, diatomine or phycoxanthine.'' It appears, then, according to the foregoing quotation, 
that it is not impossible for diatoms to be the cause of the green tint iu Oysters, which, let me 
remark, is very nearly that of some pale green forms of those organisms which I have observed in 
water from oyster coves where I have conducted microscopic studies. Both green and brown 
diatoms may frequently be found in the stomach, and in making examinations to discover them 1 
find it best to thrust the nozzle of a pipette directly into the stomach through the mouth and 
oesophagus. The pipette should have a compressible bulb, so as to enable one to draw up the 
contents of the gastric cavity into the tube without injuring the animal or taking up any fragments 
of it to vitiate the experiment. 

Observations of Gaillon and Johnston. — Speaking of the abundance of the Navicula 
ostrearia of Kiitzing, M. Benjamin Gaillon, in 1820, said that they inhabit the water of the 
tanks or " parks " in which the Oysters are grown iu such immense abundance, at certain seasons 
of the year, that they can only be compared to the grains of dust which rise in clouds and 
obscure the air iu dusty weather. Dr. Johnston, speaking of the French Oysters, says that in 
order to communicate to them a green color, which, as with us (in England), enhances their 
value in the market and iu the estimation o + ' the epicure, they are placed for a time in tanks 
or "parks," formed in particular places near high-water mark, and into which the sea can be 
admitted at pleasure by means of sluices; the water being kept shallow and left at rest is 
favorable to the growth of the green Confervce and Ulvce; and with these there are generated 
at the same time innumerable crustaceous animalcules which serve the Oysters for food and 
tincture their flesh with the desirable hue. 

This last remark of Dr Johnston's at first struck me as improbable, but I have met with great 

numbers of small crustaceans, Copepoda mainly, in the branchial cavity of the common Clam (Mya 

arenaria). Certain peculiar species have also been described by Allinan from the branchial 

cavities of ascidians. More recently, while investigating the contents of the stomach of the 

Oyster, by the method already described, I find that it also swallows crustaceans, which are digested 

and absorbed as food. The tests of nauplii or very minute' larval crustaceans with the contents 

digested out were frequently met with. Doubtless many very small Copepoda are also swallowed 

and digested, but these are not green. Besides the foregoing, I sometimes met with the very young 

shells of larval gasteropods and lamellibranchs; indeed, it is not improbable that the adult Oyster 

may consume its own larvae. The remains of bryozoa were also observed, such as Pedicellina 

americana. The test of a peculiar elongate rhizopod and the cephalula stage of several worms 

were also noticed. Of the smaller organisms usually associated with more or less clearly marked 

47 p 



738 NATURAL HISTORY OF AQUATIC ANIMALS. 

putrefactive changes, one which I find almost uniformly present is a filiform or thread-like organ- 
ism allied to Spirillum. It, however, was always found in the stomach in great abundance, and 
especially in the pyloric portion of the iutestine in which the crystalline style is lodged. This 
organism is probably harmless; a similar one is frequently found in both fresh and salt water, 
and has at times been developed in prodigious numbers in the reservoirs from which the supplies 
of water were drawn for a large city, without any evidence of its having produced a harmful 
effect upon those who drank of the water. 

Views of Leidy, Puysegtjk, and Decaisne.— Professor Leidy, at a recent meeting of 
the Academy of Natural Sciences <>f Philadelphia, stated it as his belief that Oysters feed at 
times on the zoospores of certain algae, as those of TJlva latissima (sea cabbage), which he knew 
from personal observation to be green, and which he thought might possibly be the cause of 
the green coloration of the soft parts of the animal as sometimes observed in certain localities. 
Very possibly this may be the case, but judging from what I have seen and heard from oyster- 
men, as well as from what I have read in various publications relating to this matter, I am not 
inclined to regard this as the only source of the unusual green tint of the flesh of the Oyster. 
I hope to be able to show that it is probably of vegetable origin, and therefore quite harmless. 
That it is not copper we may be equally certain, as Professor Lewis' tests have shown, for 
any such quantity of a copper salt as would produce the green gills, heart, and cysts in the 
mantle, such as are often observed, would, without doubt, be as fatally poisonous to the Oyster 
as to a human being. The source of the green has recently been investigated by two French 
savants, MM. Puysegur and Decaisne, who found that when perfectly white-fleshed Oysters 
were supplied with water containing an abundance of a green microscopic plant, the Navicula 
ostrearia of Kiitzing, their flesh acquired a corresponding green tint. These investigators also 
found that if the Oysters which they had caused to become imbued with this vegetable green 
were placed in sea-water deprived of the microscopic vegetable food the characteristic color would 
also disappear. Whether this will finally be found to be the explanation in all eases remains to 
be seen, as some recent investigations appear to indicate thai ii is possible that a green coloration 
of animal organisms may be due to one of three other causes besides the one described above as 
the source of the green color of the Oyster. 

Geddes upon chlorophyl-containing animals. — Patrick Geddes, in a recent number 
of "Nature," has pointed out that the "list of supposed chlorophyl-containing animals . . . 
breaks up into three categories: first, those which do not contain chlorophyl at all, but green 
pigments of unknown function (Bum Ilia. Idotea. etc.) ; secondly, those vegetating by their own 
intrinsic chlorophyl (Convoluta, Spongilla, Hydra); thirdly, those vegetating by proxy, if one may 
so speak, rearing copious alga? in their own tissues, and profiting in every way by the vital 
activities of these." This latter is one of the most interesting and important of modern biological 
discoveries, that living animal bodies may actually afford a nidus for the propagation of green 
microscopic plants and not be injured but rather be benefited thereby. The oxygen thrown 
off by the parasitic vegetable organism appears to be absorbed by the tissues of the animal host. 
while the carbonic-acid gas thrown off by the latter is absorbed by the vegetable parasite, thus 
affording each other mutual help in the processes of nutrition and excretion. This singula] 
association and interdependence of the animal host and vegetable guest has received the some 
what cumbrous name of Symbiosis, which may be translated pretty nearly by the phrase "asso- 
ciated existence." This is not the place for the discussion of the purely scientific aspect of this 
question as already ably dealt with by Dr, Brandt, Patrick Geddes, Geza Entz, and others, and 



THE GREEN MATTER IN AXLMAI.s. 739 

we will therefore only notice their researches in so far as they appear to have a bearing upon 
the origin of the green color of the Oyster. 

Entz' discoveries. — Entz has discovered that he could cause colorless infusoria to become 
green by feeding with green palmellaceons cells, which, moreover, did uol die after the death <>1' 
their hosts, but continued to live, growing and developing within the latter until their total evolu 
tion proved them to be forms of very simple microscopic green algae, such as Palmetto, GUeocystis, 
etc. My own observations on some green-colored infusorial animals have been of so interesting a 
character that I will here describe what [observed in a green bell animalcule ( Vorticella chloro- 
stigma). Upon investigating their structure, 1 found that next the cuticle or skin in the outer soft 
layer of their bodies, known as the "ectosarc," at all stages there was a single stratum of green 
corpuscles very evenly or uniformly imbedded. In another form [Stentor), as already noticed by 
Stein, the same superficial layer of green corpuscles was observed, reminding one very forciblj of 
the superficial layer of chlorophyl grains observed in the cells of some plants, as. for instance, 
Anacharis. Now, it is well known that certain animalcules are at times quite colorless and at 
others quite green; this appears to be the case with Qphrydium. In this last case I have a 
suspicion that vegetable parasites may be the cause of the green variety, but as for the others, 
Stentor and Vorticella, I am not so sure that their green forms are so caused. In them the 
superficial positions of the green corpuscles and their behavior toward reagents lead me to 
think that they must be regarded as integral parts of the creatures in which they are found. 

Nature of the green matter in animals. — A grass-green planarian worm {Gonvoluta 
Schultzii), found at Eoscoff by Mr. Geddes, was observed by him to evolve oxygen in large 
amounts, like a plant, and "both chemical and histological observations showed the abundant 
presence of starch in the green cells; and thus these planarians, and presumably, also, Hydra, 
Spongilla, etc., were proved to be truly vegetating animals." While some organisms, like the 
foregoing, appear to have true chlorophyl grains imbedded superficially in their own substance, 
others, like the radiolarians, some siphonophores, sea anemones, and jelly-fishes, harbor true 
vegetable parasites, or, preferably, vegetable guests. 

That the green observed in a number of animal organisms is of the nature of chlorophyl, 
or leaf green, has been proved by Lankester by means of the spectroscope. A. W. Bennett, in 
alluding to Lankester's observations, says: "In all cases the chlorophylloid substance agrees in 
having a strong absorption band in the red — a little to the right or left — and, except in Idotea, in 
being soluble in alcohol, and in having strong red fluorescence, and in finally losing its color when 
dissolved." 

The vegetable organisms which have been found to inhabit the lower forms of life alluded to 
in the foregoing paper have been regarded as belonging to two genera, which Dr. Brandt has 
named Zoochlorella and Zooxanthella, and which are probably in part synonymous with the genus 
Philozobn, afterwards proposed by Mr. Geddes. The latter gentleman, however, claims to have 
first demonstrated the truth of the view that the yellow cells of radiolarians and polyps are algae; 
secondly, the foundation of the hypothesis of the lichenoid nature of the alliance between algae 
and animal into a theory of mutual dependence; and, thirdly, the transference of that view from 
the region of probable speculation into that of experimental science. 

Hitherto no one has apparently noticed the occurrence of green vegetable parasites in 
bivalve mollusks except Professor Leidy, who has very kindly permitted me to use the facts 
observed by him relating to Anodon, one of our common fresh-water Mussels. In this animal he 
some years ago observed what must be considered to be algous parasites. He found them in 
great numbers infesting the tissues of the Mussel and of a larger size than the nuclei of the cells of 
the host in which they were imbedded. They were also provided with a nucleus, and were, there- 



740 NATURAL HISTORY OF AQUATIC ANIMALS. 

lore, not a part of the animal but a distinct vegetable organism. These tacts, observed a long 
time since, render it very probable that Professor Leidy was one of the first to notice the intra- 
cellular parasitism of a plant in an animal. 

The green color of the Oyster, as far as my experience goes, is not intense, as in many green 
animals, such as we observe in Mentor, Spongilla, Hydra, etc., but is a pale pea green tint. This 
has been found to be the. color of affected natives as well as of foreign ones, the gills and mantle 
being usually most distinctly tinged. Exceptionally the heart is affected, its color sometimes 
being quite intense. 

Experiments upon European Oysters.— In studying some Oysters which were obtained 
from England through the kind offices of Messrs. Shaffer and Blackford, in response to a request 
coming from Professor Baird, certain ones were found which were decidedly green. Of these the 
French specimens of Ostn-n edulis, and a very singular form, labeled "Anglo-Portuguese," had the 
gills affected, and in some of the latter the liver, heart, and mantle were very deeply tinged in 
certain parts, so much so that I decided to make as critical an examination as my resources could 
command. 

Spectroscopic investigations gave only negative results, as it was found impossible to discern 
any positive evidence of chlorophyl from the spectrum of light passed through thin preparations 
made from specimens of green-tinted Oyster, some of which, like those made from the heart, are 
decidedly green to the naked eye. There was no absorption noticed at the red and blue ends of 
the spectrum, such as is observed when the light which enters the slit of the spectroscope firsl 
passes through an alcoholic solution of leaf green or chlorophyl ; indeed, the spectrum did not 
appear to be sensibly affected by the green substance which causes the coloration of [lie Oyster- 
No attempt was made to test the matter with the use of alcoholic green solutions obtained from 
affected Oysters, as the former are not easy to get with a sufficient depth of color, because of the 
relatively small amount of coloring matter present in the animals. Unstained (fresh) preparations 
were used in all of these experiments. 

Colors in different parts. — I find the liver to be normally of a brownish-red color in 
both the American and European Oyster, sometimes verging toward green. When the flesh or 
gills of the animal is green, the liver almost invariably partakes of this color, luit in an into nsi- 
tied degree. The green stain or tincture appears in some eases to have affected the internal ends 
of the cells which line the follicles or ultimate saccules of the liver. This color is able to survive 
prolonged immersion in chromic acid and alcohol, and does not allow carmine to replace ii in 
sections which have been stained with an ammoniacal solution of that color, the effect oi which 
is to produce a result similar to double staining in green and red. The singular green ele- 
ments scattered through the connective tissue remain equallj well defined, and do not take the 
carmine dye. I at first believed these to be parasitic vegetable organisms, and 1 also sup 
posed 1 saw starch granules in them, which physical tests with an iodine solution tailed to con- 
firm. These large and small green granular bodies in the connective tissue, and those close to 
the intestinal wall, as well as those in the heart 1. find present in fewer numbers in white-tleshed 
Oysters, hut simply with this difference, that they are devoid of the green color. It is evident, 
therefore, that they cannot be of the nature of parasites, though the color is limited to them. 
only the surrounding tissue, except in the region of the heart, appearing of the normal tun. 
This condition of the specimens observed by me does not, however, disprove the possibility of 
the occurrence of vegetable parasites in the Oyster, where there is as much, or perhaps more 
likelihood of their occurring than in some much more highly organized animals. 

It is a fact, however, that the Oyster is singularly free from true parasites of all kinds; i lie 



COLORS OF DIFFERENT PARTS OF THE OYSTER. 741 

oyster-crab being perhaps the only creature which is ever frequently found within its valves, 
and then only as a harmless messmate. .More recently ii has l«ni mj good fortune to be able to 
study a second lot of European Oysters, in two varieties of which bhe green color was unusually 
developed, especially in the heart. In a specimen of Palmoutb Oyster I found a large cysl or 
sac in the mantle near the edge filled with green cells, \\ Inch, like those in 1 1 1 * - heart, when opened 
readily separated from one another, being quite as independent oi cadi other as tin- ordinarj 
discoidal corpuscles in the serum of red blood. The hearts of affected specimens were found to 
have the wall of the ventricle abnormally thick, and covered inside with the readily detachable 
green cells in a thick layer and measuring one three-thousandth of an inch in diameter. An appli 
cation of the test for starch with iodine gave a negative result. If iodine was fust applied to 
these cells in strong solution, and they were then treated with sulphuric acid, the characteristic 
blue reaction was not developed, showing that there was no cellulose wall covering them, and 
that they were most positively not parasitic, algous vegetable organisms. In potassic hydrate 
solution they were completely dissolved, a further proof of the absence of cellulose. 

Their dimensions, one three-thousandth of an inch, is the same as that of the blood-cell of the 
Oyster. They are nucleated, with the nucleus iu an eccentric position as in the blood-cell of the 
animal. Their occurrence in the heart and gills so as to tinge those organs of their own color is 
almost positive proof of their true origin and character. Furthermore, I hud iu sections that they 
sometimes occlude the blood-channels. In the cysts in the mantle, as in the heart, they are free, 
and in the normal untiuged heart they are not abundant. All of the foregoing facts indicate thai 
these green bodies are in reality blood-cells which belong to the animal. How they become green 
is not easy to determine. The fact remains that no evidence of the presence of green Micrococci 
or Microtia, as independent existences, could be made out. The fact that I found instances in green 
Oysters where an unusual greenish material was found in the follicles of the liver, the living cells 
of which were also affected, would indicate that the color was probably absorbed from the food of 
the animal, which, as we know, consists largely of living vegetable matter. It is not improbable 
that the tinged nutritive juices transuded through the walls of the alimentary caual acquired the 
color of the food which had been dissolved by the digestive juices. 

How to account for the accumulation of the green cells in the heart and in cysts in the 
mantle is not, however, an easy matter, unless one be permitted to suppose that the acquisition 
of the green color by the blood-cells is in reality a more or less decidedly diseased condition, for 
which we have no ground in fact, since the green Oysters are in apparently as good health as the 
white ones. They were found 'fat' or 'poor,' just as it may have happened that their food was 
abundant or the reverse. They are also found in all stages of the ' greened' condition. Sometimes 
they have only a very faint tinge of the gills, or they may be so deeply tinged as to appear 
unpalatable, with the heart of a deep green, or with green cysts developed in the mantle, or with 
clouds of this color shading the latter organ in certain places. A vastly greater proportion of 
green Oysters are eaten in this country, at all events, than is generally supposed, especially of 
those just faintly tinged in the gills. 

The most important glandular appendage of the alimentary tract of the Oyster is the liver. 
It communicates by means of a number of wide ducts with a very irregularly formed cavity, which 
we may designate as the stomach proper, in which the food of the animal comes into contact with 
the digestive juices poured out by the ultimate follicles of the liver, to undergo solution preparatory 
to its absorption during its passage through the singularly formed intestine. 

If thin slices of the animal are examined under the microscope we find the walls of the 
stomach continuous with the walls of the great ducts of the liver. These great ducts divide and 



742 NATURAL HISTORY OF AQUATIC ANIMALS. 

subdivide until they break up into a great number of blind ovoidal sacs, into which the biliary 
secretion is poured from tbe cells of their walls. A thick stratum of these follicles surrounds the 
stomach, except at its back or dorsal side. It is not correct to speak of the liver of the Oyster as 
we speak of the liver of a higher animal. Its function in the Oyster is the same as that of three 
different glands in us, viz, the gastric follicles, the pancreas, and the liver, to which we may add the 
salivary, making a total of four in the higher animals which is represented by a single organ in 
the Oyster. In fact, experiment has shown that the secretion of the liver of mollusks combines 
characters of at least two, if not three, of the glandular appendages of the intestine of vertebrated 
animals. There are absolutely no triturating organs in the Oyster for the comminution of its 
food; it is simply macerated in the glandular secretion of the liver and swept along through the 
intestine by the combined vibratory action of innumerable fine filaments with which the walls of 
the stomach, hepatic ducts, and intestine are. clothed. 

In this way the nutritive matters of the food are acted upon in two ways: first, a peculiar 
organic ferment derived from the liver reduces them to a condition in which they may be absorbed; 
secondly, in order that the latter process may be favored it is propelled through an intestinal 
canal which is peculiarly constructed so as to present as large an amount of absorbent surface as 
possible. This is accomplished by a double induplication or fold which extends for the whole 
length of the intestine, the cavity of which in consequence appears almost crescent-shaped when 
cut straight across. On the concave side the intestinal wall is thrown into numerous very narrow 
longitudinal folds, which further serve to increase the absorbing surface. Such minor folds are 
also noticed in the stomach, and some of these may even have a special glandular function. There 
are no muscular fibers in the wall of the intestine as in vertebrates, and the sole motive force 
which propels the indigestible as well as digestible portions of the food through the alimentary 
canal is exerted by the innumerable vibratory cilia with which its inner surface is clothed. The 
intestinal wall is wholly made up of columnar cells which are in direct contact externally with 
the connective tissue which is traversed by numerous large and small bloodvessels devoid of 
specialized walls. 

This apparatus is admirably suited to render the microscopic life found in the vicinity of the 
animal available as a food supply. The vortices created by the innumerable vibratory filaments 
which cover the mantle, gills, and palps of the Oyster enables it to draw its food toward itself, 
and at the same time the microscopic host is hurled into the capacious throat of the animal to 
undergo conversion into its substance as described above. The mode in which the tissues may 
become tinged by the consumption of green spores, diatoms, or desmids it is easy to infer from 
the foregoing description of the digestive apparatus of the animal; and the colorless blood-cells, 
moving in a thin, watery liquor sanguinis, would, judging from their amoebiform character, readily 
absorb any tinge acquired by the latter from the intestinal juices. 



217. LOCAL VARIATIONS IN THE FORM AND HABITS OF THE OYSTER. 

Mr. Darwin ("Variation of Animals and Plants." vol. ii, 2d ed., p. 270) writes: "With 
respect to the common Oyster. .Mr. V. Buckland informs me that he can generally distinguish the 
shells from different districts; young Oysters brought from Wales and laid down in beds where 
'■natives'' are indigenous, in the short space of two months begin to assume the 'uative' character. 
M.Costa 1 has recorded a much more remarkable case of the same nature, namely, that young 

1 Bull, de la Soc. Imp. d'Acclimat., viii, p. 351. 



EFFECT OF BEAT Tl'ON OYSTERS. 743 

shells taken from the shores of England and placed in the Mediterranean at once altered their 
manner of growth ami formed prominent diverging rays, like those on the shells of the proper 
Mediterranean Oyster. The same individual shell, showing both forms of growth, was exhibited 

before a society in Paris." 

Variations in the shell.— The statement by Mr. Buckland m regard to the local forms of 
Ostrea edulisis undoubtedly true, as I know from personal observation of specimens itained for 
me from various parts of Europe through the efforts of Professor Baird. In some cases the local 
differences between the shells from different places were so marked thai had a person mixed certain 
lots together indiscriminately without my knowledge 1 could afterwards certainly have soiled out 
the more marked varieties. Local influences also very largely determine the "greening" of ( >.\ sters, 
as I can assert from personal observation of both the American and European species. Practical 
oystermen affirm that they can readily discriminate the local varieties of Oysters grown in various 
noted localities along the eastern coast of the United States. From what I have seen it is very 
probable that this may be the case, as one may often observe well-marked differences of form as 
well as color. 

Local adaptation undoubtedly takes place, for how else are we to account for the fact that 
a change in the specific gravity of the water to which the adult has been accustomed will kill the 
milt? This point has an important practical bearing in relation to the effect of heavy rains in 
diluting the water when the auiruals are spawning. Might not a marked change in the specific 
gravity of the water at the time of spawning kill all the spermatozoa which are set free, and thus 
also prevent the impregnation of whatever mature ova were being thrown out at that time by 
the adults? 

Influence of teiuperature. — Certain it is that temperature has an influence upon the 
time of spawning. A lot of Oysters marked "Anglo-Portuguese," which had been transplanted 
from Portuguese to English waters, and which I received in the month of March aud others 
in January last, had the reproductive organs remarkably advanced in development as compared 
with specimens of 0. edulis from different parts of England, Wales, Scotland, Holland, and France. 
So great was this difference that, although planted for some time in the colder waters of England, 
the reproductive organs of the Portuguese form had not apparently had their disposition to 
become functionally active at this early season influenced to any great extent. In fact, I obtained 
living mature eggs and milt from a number of specimens of this variety, while I looked in vain 
for ripe spawn in any of the others of the true 0. edulis. This would indicate that the influence ot 
temperature, though not altogether hereditary in this case, was persistent, and had so impressed 
itself that the reproductive organs of these Oysters, coming from a warmer latitude, had begun 
to mature their sexual products even after transplanting into more northerly and colder waters 
much sooner than the natives of those same latitudes. 

Like this persistent influence of a climate to which certain forms of Oysters have been long 
accustomed, the influence of the specific gravity of the water of a certain locality may also be 
persistent. The Oysters of Saint Jerome's Creek seem to be adapted to the specific gravity of 
the water of the vicinity, so that if artificial sea- water is prepared, differing much in this regard 
from the native water, we find that the spermatozoa are immediately killed if put into it. From 
this it follows that if the specific gravity to which the adults become accustomed is normal to 
their sexual products, may it not be well to look into the effect of such changes upon the health 
of the adults ? 

I have met with spawning Oysters in December, such at least in which the spawn was nearly 
mature, but this was an exceptional case. I find them in April and May in considerable abun- 



744 NAT PEAL HISTORY OF AQUATIC ANIMALS. 

dance; the mouths of May, June, and July may, however, be regarded as their principal spawning 
months. Ripe spawn may be sparingly obtained in the latter part of August, and even up to 
the first of October, but the three months mentioned are the periods during which the experi- 
mentalist ought to be in the field prepared for work in this, the latitude of Washington. What 
amount of variation from this period may be made manifest as we go north or south along the 
eastern coast of the United States I am unable to state; and what amount of local variation may 
also be due to causes of a purely local character I am also unable to say, not having examined 
the Oysters at a sufficient number of localities" to make such facts as I may possess of any 
value. 

218. THE OYSTER-CRAB AS A MESSMATE AND PURVEYOR. 

It is many years since Mr. Say named the little Oyster-crab Pinnotheres ostreum, and its habits 
since that time seem to have excited but little interest. Professor Verrill, in his observations pub- 
lished in the "Report of the United States Fish Commissioner for 1871-72," records the fact that 
it is the female which lives in the Oyster, and that the male, which is smaller and unlike the 
female, especially in the form of the abdominal segments of the body, is rarely if ever seen to 
occur as a messmate of the Oyster, but that he has seen it swimming at the surface of the water 
in the middle of Vineyard Sound. He also says that they occur wherever Oysters arc found. 
This singular little crab has quite a number of allies which inhabit various living mollusks, holo- 
thurians, etc., of which admirable accounts are given by Van Beneden in his work on "Animal 
Parasites and Messmates," and also by Semper in his treatise entitled " Animal Life." 

Quadruple commensalism. — The Oyster-crab is a true messmate, and it is in the highest 
degree probable that the presence of these animals in the mantle cavity of the Oyster is to be 
regarded as advantageous rather than otherwise. The animal usually lives between the ventral 
lobes of the mantle of its host, into which the four lobes of the gills and palps also depend, 
and, as will l>e seen from the following observations, may be the means of indirectly supplying 
its passive protector with a portion of food. During a trip down the Chesapeake in July. 1SSI), 
while I was with (he Pish Commission vessel, some Oysters were dredged up bj the crew which 
contained some Oyster-crabs. In the case 1 am about to describe the included Crab was a female 
with I lie curiously expanded, bowl like abdomen folded forward under the thorax, partially 
covering a huge mass of brownish eggs. Upon examining these eggs, what was my astonish- 
ment to find that they afforded attachment to a great Dumber of compound colonies of the 
singular bell animalcule, Zoothamnium arbuscuVum. (Tpon further examination it was found that 
the legs and back of the animal also afforded points of attachment for similar colonies, ami 
that licic and there, where some of the individuals of a colony of Zoothamnium had been sepa 
rated from their stalks, numerous rod-like vibriones had affixed themselves by one end. In this 
way it happens that there is a quadruple commensalism established, since we have the vibriones 
fixed and probablj nourished from the stalks of the bell animalcule, while the latter is benefited 
by the stream of water drawn in by the cilia of the Oyster, and the last feeds itself and \ts.protegS, 
the crab, from the same food laden current. Possibly the crab inside the shell of its host catches 
and swallows food which in its entire state could nor be taken by the Oyster, but in any event 
the small crumbs which would fall from the month and claws of the crab would be carried to 
the mouth of the Oyster, so that nothing would be wasted. 

We must consider the crab with its forest of bell animalcules in still another light. Since 
the animalcules are well fed in their strange position, it is but natural to suppose that they would 



DEVELOPMENT OF THE OYSTER-CRAB. 745 

propagate vapidly, and that the branches of the curious treelike colonies would also increase in 
numbers. The individuals of the colonies multiply in aboui three ways: first, by branching; 
secondly, by splitting lengthwise; thirdly, certain much enlarged and overfed zooids di\ ide cross- 
wise. By the two last modes one-half of the product is often sel free, the tree animalcules 
so originated being known as "swarmers." These cast oil or free zooids which drop from the 
colonies are no doubt carried along by the vortex created bj the cilia of the gill and palps, and 
hurled into the mouth and swallowed as part of the daily allowance 6f the food of the Oyster. 
We may therefore regard Pinnotheres, in such instances, as a veritable ourserj . upon the body and 
legs of which animalcules are continually propagated and set tree as part of the food supply of 
the Oyster, acting as host to the crab. I do not suppose, however, that such a condition will 
always be found to obtain, and it must also be remembered that myriads of Zoothamnium colonies 
were dredged up attached to the fronds of the handsome Grinnelia, a red alga commonly found 
in certain parts of Chesapeake Bay. Where this plant grows in abundance on the bottom 1 have 
estimated that one might find upwards of a hundred animalcules attached to a square inch of 
frond surface, which would indicate an animalcnlar population of upwards of four millions of 
individuals to the square rod, a number as great as that of the human inhabitants of the city of 
London. 

Development of the Oyster-crab. — The Oyster-crab undergoes a development and 
metamorphosis similar to that of our edible crab, Callineotes, but the body in the Zosea stage 
is blotched with dark, branched pigment cells. The eyes also are vastly more developed than 
in the adult, where they are partly suppressed from disuse. There is no dorsal spine, nor are 
the antennary and rostral appendages so well developed as in the Zoaea of Gallinectes. After the 
young are hatched they probably leave the abdominal covering of the parent, swim out of the 
Oyster for a season, and, if female, seek a permanent abode in some Oyster near by, behaving 
somewhat like the species described by Semper as inhabiting the water-lungs of certain holotliu- 
rians. After undergoing further development, the young Pinnotheres reaches the megalops stage 
of its development, when it is probable that the choice of its home takes place. After it has 
entered the mantle cavity of its host as a diminutive larva, and has grown to be adult, when 
it measures a half inch or more in diameter, it is probably ever after a prisoner within the 
shell of its molluscan protector. It undergoes a retrogressive metamorphosis as it grows adult, 
its eyes become relatively less conspicuous than in youth, and it never has a thick, hard shell 
like its allies which live in the open water, but the external skeleton remains almost entirely soft 
and chitinons, or in the state in which we commonly find the outer covering of an edible crab 
which has just molted. This arises apparently from the conditions by which the animal is sur- 
rounded; the protection afforded it by its host does away with the need of a thick, hard covering 
such as we find inclosing the bodies of its free-swimming allies. Unlike the latter, too, the limbs 
of the Oyster-crab are to some extent degenerate and weakened; its chelae or claws are feeble, 
and, when removed from its home, seems a very sluggish, helpless sort of creature, without a 
particle of the pugnacity of its allies, and if placed on its back will sometimes remain in that 
position helplessly beating the air with its weak limbs. This is a remarkable instance, which also 
serves very admirably to illustrate the principle of degeneration in organic evolution, so ably 
dealt with by Prof. E. Bay Lankester. 

The Oyster itself is also an example of.the effect of disuse in producing retrograde develop- 
ment, and even shows signs of gradual adaptation when removed from one locality to another. 
Unlike most other bivalves, the Oyster has no soft muscular foot which it may protrude outward 
from between the edges of its valves. No visible rudiment of such a prominence can be found 



,46 NATURAL HISTORY OF AQUATIC ANIMALS. 

in the adult, though something of the sort, it is asserted by embryologists, appears to be devel- 
oped in the larvaB. As the Oyster lost its power of locomotion from the non -development of 
the foot, due doubtless to a gradually acquired sedentary habit winch bas become permanent, 
the pedal structures have been almost entirely aborted, leaving nothing excepting the poorly 
developed pedal muscles described by Dall. There is accordingly little or no evidence of the 
existence of a pedal or foot ganglion in the Oyster, because there is no need for one, as in other 
forms; it, too, has disappeared with the structure which required its presence. 

Returning to the consideration of the Oyster-crab, it is well known that it is much relished 
by many persons. The animal may be eaten alive, and has a peculiar, agreeable sweetish taste. 
Recently an enterprising New York party has taken to canning them, the supplies for this purpose 
being obtained from some of the large oyster-canning establishments. The economic value of the 
animal as food, although not great, is sufficiently important to demand a passing notice. 

219. PHYSICAL AND VITAL AGENCIES DESTRUCTIVE TO OYSTERS. 

Most of the observations which follow were made at Saint Jerome's Creek, Maryland, but 
inasmuch as the physical and vital enemies of Oysters appear to l>c similar the world over, I have 
no hesitation in reproducing what I have previously published elsewhere. And of physically 
injurious agents the black ooze or mud found in the vicinity or on the bottom of many of our 
most valuable beds and planting grounds is probably the most to be dreaded if it accumulates 
in too great quantity. 

The origin of the black ooze at the bottom can be traced directly to the sediment held in 
suspension in the water which slowly ebbs and Hows in and out of the inclosure, earning with it 
in its going and coining a great deal of light organic and inorganic debris, the former part of which 
is mainly derived from the comminuted fragments of plants growing in the creek. This seemed to 
be the true history indicated by what was noticed in studying the box-collector. The same opinion 
is held as to the origin of this mud by both ( Joste and Fraiche in their works on oyster-culture. 

There is probably no worse enemy of the oyster-culturist than this very mud or sediment. 
It accumulates on the bottom of the oyster-grounds, where in course of time it may become deep 
enough to cause serious trouble. Especially is this true of pouds from which the sea ebbs, and to 
which it flows through a narrow channel. Tin; tailing leaves from neighboring trees in autumn 
also contribute to this pollution, as well as heavy rains which wash deleterious materials into it. 

Adult Oysters which are immersed in part in this mud struggle hard to shut it out from 
their shells. If one will notice the inside of the shells of Oysters which have grown in a muddy 
bottom, it will often be seen that there are blister-like cavities around the edges of the valves 
tilled with mud, or a black material of a similar character. There is not the slightest doubt 
m my mind that in these cases the animal, in order to keep out the intruding mud, has had 
recourse to the only available means at its command. A great many of the Oysters in the pond 
an' affected in this manner, but it is extremely uncommon to find shells of this kind in opening 
Oysters coming from a hard bottom. It is easy to understand that such efforts at keeping out 
the mud from the shell will not only waste the life Ibices of the animal, but also tend to greatly 
interfere with its growth. The importance, therefore, of artificial preparation is apparent, where 
it is desirable to establish ponds for the successful culture of this mollusk. 

Only in one ease have 1 observed that the mini tended to impair the flavor and color of 
the Oyster. In this instance the animal was thoroughly saturated with the black ooze, the very 
tissues seeming to be impregnated with the color, the si ach and intestine loaded to engorge- 
ment with the mud, the animal manifesting every sign of being in a decidedly sickened condition. 



EFFECT OF SEDIMENT UPON YOUNG OYSTEES. 747 

The cause of this was probably that the shell with its tenant had sunken too deeply into the 
mud when the iugestion of the black ooze commenced, giving rise to the remarkable changes 
which I have recorded. No doubt had this condition of things persisted for long the animal 
would have been smothered by the mud. 

Mud and the young fry.— The accumulation of the slightest quantity of sediment around 
a young Oyster would tend to impede its respiration, and in thai waj destroy it, yet in the natural 
beds there are so few naturally clean places which remain so thai it is reallj surprising that so 
many young Oysters pass safely through the critical periods of their lives without succumbing to 
the smothering effects of mud and sediment. When it is borne in mind that at the time the infant 
Oyster settles down and fixes itself once and lor all time to one place, from which it lias no power 
to move itself, it measures at the utmost one-eightieth of an inch, it will not be hard to under- 
stand how easily the little creature can be smothered even by a ven small pinch of dirt. The 
animal, small as it is, must already begin to breathe just in the same way as its patents did before 
it. Like them its gills soon grow as little filaments covered with cilia, which cause a tiny currenl 
of water to pass in and out of the shell. The reader's imagination may be here allowed to esti- 
mate the feeble strength of that little current, which is of such vital importance to the tiny Oyster, 
and the ease with which it may be stopped by a very slight accumulation of dirt. Mobius esti- 
mates that each Oyster which is born has 114 ^ 000 of a chance to survive and reach adult age. So 
numerous and effective are the adverse conditions which surround the millions of eggs matured by 
a single female that only the most trifling fraction ever develop, as illustrated by the above calcu- 
lation. The egg of the Oyster, being exceedingly small and heavier than water, immediately falls 
to the bottom on being set free by the parent. Should the bottom be oozy or composed of 
sediment its chances of development are meager indeed. Irrecoverably buried, the eggs do not 
in all probability have the chance to begin to develop at all. The chances of impregnation are 
also reduced, because the male and female Oysters empty their generative products directly into 
the surrounding water, whereby the likelihood of the eggs meeting with the male cells becomes 
diminished. What with falling into the mud and what with a lessened chance of becoming 
impregnated, it is not unlikely that Mobius' estimate is very nearly correct; but the American 
Oyster, whose yield of eggs is much greater, not only on account of its larger size, but also 
because the eggs are smaller than those of the European, has probably still few r er chances of 
survival. The vigorous growth of small organisms on surfaces fitted for the attachment of young- 
Oysters also tends to cause sediment to gather in such places in the interstices of the little 
organic forest, where the eggs of the Oyster no doubt often become entombed or smothered by the 
crowded growth surrounding them. 

" In addition to the active, animate enemies of the Oyster, the beds suffer seriously, at certain 
times, from the elements. . . . Great storms will sweep the Oysters all off the beds, bury 
them under shifting sand or mud, or heap upon them the drifting wrack torn from the shores. 
Beds which lie at the mouths of rivers are liable to be injured by floods also, which keep the 
water wholly fresh, or bring down enormous quantities of silt and floating matter, which settles 
on the beds and smothers the Oysters. 

"A few years ago a large tract of peat was drained at Grangemouth, Scotland. The loose 
mud and moss was carried down the drains upon an oyster-bed in the estuary ; the consequence 
was that the Oysters were covered over with mud and entirely destroyed. Nothing is so fatal to 
Oysters as a mud storm, except it be a sand storm. The mud and the sand accumulate in the 
Oyster's delicate breathing organs and suffocate him. 

" North of Long Island an enemy is found which does not exist in the milder south, in the 



748 NATURAL HISTORY OF AQUATIC ANIMALS. 

shape of 'ground-ice' or 'anchor-frost.' It is little understood, thougb often experienced, and I 
was able to collect only vague data in regard to it. It appears that in hard winters the bottom of 
the bays freezes solid in great patches, even at a depth of fifteen or twenty feet. The mud freezes 
so hard that rakes cannot be pressed into it; and if a stronger implement, like a ship's anchor, is 
able to penetrate it. the crust comes up in great chunks. These frozen patches are sometimes 
forty feet square and continue unthawed for long periods. When such 'anchor-frost' takes place 
at an Oyster-bed, of course the mollusks are frozen solidly into the mass, and few of them ever 
survive the treatment. To the Cape Cod planters this is a serious obstacle to success."' 

Interference of other animae life. — We have called attention to the probable inter- 
ference of small organic growths to the fixation of the young fry; in practice it is found that the 
larger organic growths which establish themselves on the collectors also become injurious. The 
two most conspicuous types are the sessile ascidians or tuuicates and the barnacles. I have 
frequently found fully one-half of the surface of a slate covered with a dense colony of ascidians; 
in this condition a great percentage of available surface is lost which ought to serve for the 
attachment of spat. The surfaces so occupied would also be comparatively clean were it not for 
these organisms, which actually become a serious annoyance. They, like the Oyster, affix 
themselves to the slates while still in the free swimming larval stage, since the surfaces designed 
for the Oyster are equally well adapted to them. The barnacles, which also affix themselves in 
great numbers, become a nuisance for the same reason. The larval barnacle is an extremely 
active little creature, and dashes about in the water with great rapidity. As soon as it has 
completed this stage of its growth it betakes itself to some object, to the surface of which it 
attaches itself bj the head end, when a singular change takes place, at the end of which it is 
found that it has begun the construction of the curious conical shell which it inhabits. They 
grow very rapidly, so that in a couple of months the shell will already measure over half an inch 
in diameter. In this way further inroads are made upon the room which should be taken up by 
Oysters. 

Of course the larger types are nor alone in taking up space, since infusorians, bryozoans, 
polyps, etc., are also culpable, as well as algae, such as diatoms and the higher forms. The only 
remedy for this accumulation of animal growths on the surfaces of the slates and other collecting 
apparatus will be to have the frames which hold the slate in position so arranged that each tile, 
shingle, or slate can be removed, in order that it may be readily overhauled and these organisms 
removed from the surfaces which it is desired shall remain clean. This work would have to be 
done at intervals of every two or three weeks, and should be conducted with great care, so as not 
to remove the Oysters which have affixed themselves along with the other things which it is the 
intention to destroy. The removal of the smaller forms from the surfaces of the slate would be 
more difficult, and attended with danger to the fry already attached, With this object in view, 
I would suggest tin- use of wooden racks or frames lying horizontally, which would receive the 
slates mto deep notches made with a. saw, so as to hold them vertically or edgewise, rendering 
their removal, for the purposes of cleansing, and their replacement an easy matter. Other 
devices would no doubt answer the same purpose and lie more convenient even than the last. 
If posts were securely fixed in the bottom eight or ten feet apart, so as to project a foot or so 
above the water at the highest tide, a single board six inches wide, nailed against the tops of the 
posts edgewise, and extending from one to the other, would provide a simple arrangement from 
which to hang the slates singly by means of galvanized wire fastened or hooked to nails partly 
driven into the board. By the help of this plan one man with a boat could overhaul many 



'E. Ixgeesoll. Report "ii Oyster Industry, Tenth Census. 



ENEMIES OF THE OYSTEKS. 749 

hundreds of slates in a single day. and effectually care for them for a whole season. This last 
contrivance would not answer well perhaps where there was a swift current, bul would be a most 
admirable arrangement in still ponds or -claims. ' in such places the whole area might be 
provided with posts grouped or placed in rows, so that when the attendant was at worfc he could 
pass in order from one row to the other in a narrow boat, or two attendants in one boat could lake 
care of two rows, the ones on either hand, at the same time. 

Star-fishes are notorious for the havoc they arc capable of making among Oysters. Thej 
have the power apparently of everting their saccular stomachs and extracting the suit parts of 
their prey from the shell. Whole beds have been seriously injured l.y the inroads of these 
creatures. They do not seem to be dreaded much in the Chesapeake Bay, however, and appear 
to annoy the oyster-planters of Xew England most seriously. 

" The oyster- catcher, and some other birds, steal not a lew at low tide. Barnacles, annelids, 
and masses of hydroid growth sometimes form about the shells and intercept the nutriment of the 
poor mollusk, until he is nearly or quite starved; this is particularly true in Southern waters. At 
Staten Island the planters are always apprehensive of trouble from the colonization of mussels on 
their oyster-beds. The mussels, having established themselves, grow rapidly, knit the Oysters 
together by their tough threads, making culling very difficult, and take much of the food which 
otherwise would help fatten the more valuable shell-fish. In the Delaware Bay the spawn of 
squids, in the shape of clusters of egg-cases, appropriately called ; sea-grapes,' often grows on the 
Oysters so thickly, during the inaction of summer, that when the fall winds come, or the beds are 
disturbed by a dredge, great quantities of Oysters rise to the surface, buoyed up by the light 
parasitic 'grapes,' and are floated away. This is a very curious danger. Lastly, certain crabs 
are to be feared — chiefly the GalUnectes hastatus, our common 'soft crab,' and the Cancer irroratus. 
Probably the latter is the more hurtful of the two. I have heard more complaint on this score at 
the western end of the Great South Bay, Long Island, than anywhere else. Mr. Edward Udall 
told me that the crab was the greatest of all enemies to Oysters on the Oak Island beds. They eat 
the small Oysters up to the size of a quarter-dollar, chewing them all to bits. These are on the 
the artificial beds, for they do not seem to trouble the natural growth. But tolled by broken 
Oysters, when the planter is working, they come in crowds to that point. Mr. Udall stated that 
once he put down five hundred bushels of seed brought from Brookhaven, and that it was utterly 
destroyed by these crabs within a week and while he was still planting. He could see the crabs, 
and they numbered one to every fifty Oysters. It is well known that in Europe the crabs are 
very destructive to planted beds, and it is quite possible that many mysterious losses may be 
charged to these rapacious and insidious robbers. By the way, Aldrovandus and other of the 
naturalists of the Middle Ages entertained a singular notion relative to the crab and the Oyster. 
They state that the crab, in order to obtain the animal of the Oyster, without danger to their 
own claws, watch their opportunity when the shell is open to advance without noise and cast a 
pebble between their shells, to prevent their closing, and then extract the animal in safety. 
'What craft!' exclaims the credulous author, 'in animals that are destitute of reason and 
voice.' " 1 

In a specimen of the common Ostrea virginica, recently handed me for examination by my 
friend, Mr. John Ford, the substance of the shell was thoroughly cavernated so as to render it 
extremely brittle and readily crushed; in fact, the inner table of the shell left standing showed a 
great number of elevations within, which indicated points where the intruding parasite had been 
kept out by the Oyster, which had deposited new layers of calcareous matter at these places so 



1 E. Ixgeesoll : Report on the Oyster Industry, Tenth Census. 



750 NATURAL HISTORY JF AQUATIC ANIMALS. 

as to give rise to the elevations spoken of. Besides this, the inner table had become so weakened 
at the insertion of the adductor muscles that the animal in closing had torn a part of it loose, 
which had been repaired by the deposition of a brown, horny substance. Evidence of the presence 
of the boring sponge may very frequently be noticed in shells of Oysters brought to the markets, 
though it often appears as if the parasite had left its work incomplete, being killed on its host. 
I find that Schmidt has also noted this, and that the boring operations of the sponge usually seem 
to stop in the case of living mollusks at the nacreous layer. 

Upon examining some Scotch Oysters, obtained for me for study by Professor Baird, I was 
struck with the fact that every one was infested with this organism. The effect of the parasitism 
was that all of the specimens had abnormally thick shells, due evidently to the effort made by 
the Oyster to deposit more and more calcareous matter in order to exclude its persistent tormentor. 
Internally the shell showed irregularities due to the intrusion of the sponge. It is highly probable 
that in this case the growth of the Oysters had been impeded by the parasite, in consequence of 
the effort made by the animals to exclude their enemy by increasing the thickness of their shells. 
This same tendency to increase the thickness of the valves I have noticed in specimens of our 
native Oyster, the shells of which were infested with this parasite It is very remarkable that the 
Oyster should make an effort to exclude its enemy by such a means ; and il is not less remarkable 
to observe that the lime carbonate secreting function of the mantle is often stimulated to extra 
exertion long before the parasite has actually intruded into the cavity of the shell. 

Dr. Leidy gives a lucid account of the living sponge as found in Ostrea virginiana and Venus 
mercenaria. He says: "This boring sponge forms an extensive system of galleries between the 
outer and inner layers of the shells, protrudes through the perforations of the latter tubular 
processes, from one to two lines long and one-half to three-fourths "f a line wide. The tubes are 
of two kinds, the most numerous being cylindrical and expanded at the orifice in a corolla form, 
with their margin thin, translucent, entire, veined with more opaque lines, and with the throat 
bristling with siliceous spicules. The second kind of tubes are comparatively tew, about as one is 
to thirty of the other, and are shorter, wider, not expanded at the orifice, and the throal unob- 
structed with spiculaB. Some of the second variety of tubes are constituted of a confluent pair, 
the throat of which bifurcates at bottom. Doth kinds of the tubes are very slightly contractile, 
and under irritation may gradually assume the appearance of superficial, wart like eminences 
within the perforations of the shell occupied by the sponge. Water obtains access to the interior 
of the latter through the more numerous tubes, and is expelled in quite active currents from the 
wider tubes." 

The boring process seems to be effected by the action of the living soft material of the sponge, 
according to observations which have recently been made by a Russian naturalist, according to 
whom it appears that the calcareous matter is dissolved away by the parasite. I am told by a 
practical oysterman that a. bed once planted with Oysters which are badly infested by the boring 
sponge is apt to remain so for some time, and that the beds adjoining become infested, for the 
reason that the embryo sponges, which are thrown oil' in large numbers from the infested "plants," 
swim about in the water, attach themselves to other Oysters, to begin their injurious growth and 
excavations in sound shells. 

220. NATURAL AND ARTIFICIAL OYSTER-BANKS. 

Characteristics of natural oyster-banks.— I have examined a number of oyster- 
banks, which were readily accessible in shallow water, with gratifying results as to the habits 
of the animal under virtually undisturbed conditions. These banks, like those formed by the 



POSITIONS OF THE SPAT. 751 

European Oyster, always appear to be much longer than wide, bul many of them are almost 
entirely exposed to the air during low tide, a rare occurrence, according to Mobius, with the 
banks on the Schleswig-Holstein coast of the North Sea. I learned from the owners of 
some of these banks that, although a considerable proportion of the Oysters on them were 
at times frozen to death during the severe winters, the fecundity of those which remained was 
such, combined with the naturally favorable conditions found on the banks for the growth 
of old and young, as to restore the beds to their wonted productiveness in one or two seasons. 
Whether this description of the fecundity of the beds found in shallow water is overdrawn 
or not matters little, since there was the plainest evidence that we had here before our eyes 
the best natural conditions for the propagation and feeding of the individuals. The beds are, 
in a word, natural spat-collecting grounds; plaoes where such conditions obtain as will allow a 
large proportion of the swarming brood of the spawning season to affix itself securely and survive 
in positions where an abundance of food may be go't. The tide ebbing and flowing over the> beds 
not only carries with it in suspension the microscopic food best adapted for the nourishment of the 
Oysters, but also tends, owing to the peculiar arrangement of the shells on the banks, to keep the 
surface of the latter clean, so as to be well adapted as favorable points of attachment for the young. 
In all of the natural banks which I have had the pleasure of examining in the Chesapeake, 
the individual Oysters assume an approximately vertical position. The assumption of this position 
seems perfectly natural ; with the hinge end downwards and the free edges of the valves directed 
upward the animals are in an excellent position to feed, while the outside vertical surfaces of the 
valves are well adapted to afford places of attachment for the spat. The latter, however, appears 
to attach itself in the greatest abundance to the old Oysters at the surface of the bank. The result 
is that when one removes the Oysters from the bed they are found to adhere together in clusters, 
generation after generation being piled one on top of the other in succession. As many as four 
generations may be made out in most cases ; the oldest being buried in the mud and sand below 
and is often found to be smothered by those which have followed. Even below the last stratum 
of living Oysters, if one keeps digging, it is discovered that the shells of numerous still more 
remote ancestors of the living ones now occupying the bed are disposed vertically in the sand and 
earth beneath. Attached to the upper edges of these dead shells follows, we will say, the first 
living generation and so on to the fourth, composed mainly of young individuals or spat only a 
few days or months old. Whether it is proper to regard the superimposed series of individuals as 
generations may be questioned, but as no more expressive word occurs to me, I wish to be under- 
stood as using it here with qualifications. 

Positions op the spat. — The spat does not fix itself in any constant position ; the young 
may have the hinge of the shell directed downward, upward, or to the right or left hand. 
Singularly enough the shells do not grow in the directions which the free edges of the valves 
are made to assume in the young. Should the young happen to be fixed hinge downward 
the free edges of the valves grow in length directly upward; in case the hinge is directed 
either to the right or to the left, the layers of calcic carbonate will be deposited in 
such a- way upon one side as to cause the free edges of the valves to be eventually 
directed upwards, causing the umbonal portion of the valves to describe an arc of 90°. 
In case the hinge is at first directed upward, the layers of carbonate of lime will be deposited 
in such a way by the mantle as to bring the mouth of the shell upward. The attempt to get 
into a vertical position will, however, not always be successful in cases like the last; the arc of 
180°, which it is necessary for the animal to traverse from its starting point in order to build 
its shell with the free edges opening upward, seem to be a feat a little too difficult of accom- 
plishment, in spite of the wonderful persistence of effort manifested by the inhabitant. 



752 NATURAL HISTORY OF AQUATIC ANIMALS. 

The habit of growing in the erect position, where the banks are prolific and undisturbed. 
causes the individuals to be very much crowded together, so that they do not have a chance to 
expand and grow into their normal shape. From this cause, overcrowding, the shells of the 
individual Oysters become very narrow and greatly elongated; the peculiar forms which result 
are known to oystermen as "Raccoon Oysters," or "Cat's-tongues," the latter name being probably 
derived from a suggestive resemblance to the tongue of a cat. Fossil Oysters appear to have had 
the same habit. In some banks their crowded condition may be interred from the fad that I 
counted as many as forty Oysters in an area included by a quadrangle of wire including exactly 
one square foot; thirty individuals to the square foot was a fair average on one bank 
examined. 

All of the observant writers upon the Oyster agree that it is essential that the bottom upon 
which oyster-banks are to be permanent should not be liable to shift or be covered by mud or 
sediment. The experience of the writer strongly enforces such a conclusion. The permanent 
hanks, owing to the great number of dead shells scattered through the bottom soil upon which 
they have been established, acquire a peculiar solidity or fixedness which the currents of tide water 
cannot sensibly affect. When these banks are once covered by the clusters of Oysters more or 
less securely held together by the lower portions becoming imbedded in the soil below, and 
mutually wedged and fitted together by the any msurfaces of contiguous clusters which have 
become neatly adapted to each other by pressure, it is a very hard matter for the tides to smother 
the bank unless sufficient soil in suspension is carried by the waters to completely cover the 
animals. 

Establishment of artificial beds. — The inferences to be drawn from the foregoing 
observations arc very important. They naturally lead to the inquiry whether artificial Oyster- 
beds cannot at least be established in shallow water, where the difficulties in altering the 
character of the bottom so as to adapt it to the wants of the Oyster are not practically 
insurmountable. I believe thai the establishment of artificial beds, which would in time become 
similar in every respect to. the natural ones, is possible in a moderately rapid tideway. The 
localities, 1 apprehend, are abundant along the shores of the Chesapeake, and I certainly 
know of few places where the existing natural conditions for such a project are any better 
than those found in Saint Jerome's Creek. The bottom would, of course, have to undergo such 
preparation as would insure to it solidity, and it might be well to imitate the flat, ridge like 
character of the natural banks in constructing artificial ones. The long axis of the beds should 
probably lie transversely to the direction in which the tide ebbs and flows in and out of the 
creeks, as appears to be the ease with many banks examined. The next thing to do would be 
to colonize these artificial banks with Oysters stuck thickly into the bottom, hinge downward, 
imitating the position of the animals in the natural banks. The cost of such an experimental 
bank would be comparatively insignificant. 

Since the publication of the substance of the foregoing suggestion l have seen the idea 
practically realized in the Cherrystone River, Virginia. A heap of Oyster-shells had been 
scattered so as to form a low, solid elevation, which was submerged twice a day by the tide. 
Upon tins spat had caught ami grown until the whole in two years was as completely and 
solidly covered by living natural-growth Oysters as any good natural bank. The desirability 
of using the poorly grown stock from natural and artificial banks as "seed" for planting 
appears reasonable, and could no doubt be made profitable where banks of a sufficient extent 
could be established, from which a supply of seed could be obtained. 



SPAT-OOLLEOTORS. 753 

I have been informed by an old oysterman that pine bushes sine], secure^ into the sea 
bottom so as to be submerged in shallow areas have been found very effectual as collectors. 
In fact, he told me that in one case which had fallen under his observation an oyster-planter 
who followed this plan had the satisfaction of seeing his submerged bushes load witb spat, 
much of which afterwards grew to marketable size. Afterwards a productive ridge or banli 
was the result where the brush palisade had originally acted as a collector. Thiol palisades 
of brush might be stuck into the bottom near permanent oyster-banks with good results. 
Doubtless it would be possible to establish banks by this method if, in addition, oyster-shells 
or stones were strewn on the bottom along either side of the brush palisade, in order to a fluid 
a foundation for the fixation of the first generations of oysters. 

Spat-collectors.— Lieutenant Winslow, in 1879, used hurdles or nests of half-round tiles, 
eight to sixteen in number; the results from one placed in the Big Annemessex were very flatter 
ing. After it had been immersed twenty-four days 1,506 Oysters had attached themselves. After 
forty-five days had elapsed 1,334 still remained, and after ninety-three days were past the number 
still adherent was 539. I have had no such success, but in other parts of the bay, as at Tangier 
Sound for instance, spat falls in great abundance. I have seen the inner face of one valve of a dead 
Oyster furnish attachment for over forty spat from one-eighth to three eighths of an inch in 
diameter. Sponges, pieces of wreck, old shoes, pebbles, iron ore, leather, the external surface of 
the shell of Modiolaria, branches of trees and logs which have fallen into the water act as collectors. 
Oysters are sometimes found inside of bottles which have been thrown upon the bottom, the fry 
having wandered through the neck and attached itself to the inner surface, growing to the size of 
two inches in diameter and over. The spat is shaped much like the scallop or Pecten, a form which 
it often retains until it measures more than two inches in diameter. The primary requisite in 
collectors is that they shall present clean surfaces while the spawning season is in progress. 
Small inequalities are probably an advantage, as the very youngest spat is often found in chinks 
and angles on the shells of the adults. No other organisms should be allowed to grow and cover 
up or smother the oyster spat. Barnacles, infusoria, moss animals, polyps, and many other 
organisms are liable to accumulate on the surface of the collectors to the detriment of the young 
Oysters which have established themselves. Many of these animals, polyps especially, eat the 
young fry in the free-swimming stage, as shown by Dr. Horst. 

The use of the methods employed abroad for collecting spat has not been tested in the United 
States upon a scale large enough to enable us to arrive as yet at any very important conclusions. 
Booting slate coated with mortar promises good results; the valves of oyster shells strung upon 
wire, pine cones, and brush have been used, but in unfavorable places, so as to vitiate to some 
extent the results which were expected. A coating of cement will not answer; it gets too hard, 
so that the spat when it is to be removed from the collectors cannot be loosened without injuring 
its delicate, thin valves. The coating of lime and sand should be thick enough so as to make a 
layer of at least an eighth of an inch over the surface of the collector. It should also be allowed 
to thoroughly "set," as a stone mason would say, after it has been applied so as not to wash off 
readily. A strong mortar should be mixed for the coating, composed of sharp sand and good 
lime, in the proportions of about equal parts, and thin enough to dip the slates or tiles into the 
mixture bodily. If the first coat is not found to be thick enough a second and third may be 
applied. The tiles or slates after coating should be allowed to dry for two or three days so as to 
allow the coating to " set " firmly. 
48 F 



754 NATURAL HISTORY OF AQUATIC ANIMALS. 

Various ways of supporting the tiles and slates have been devised, cheap forms of which are 
described in the treatises of Ooste and Fraiche. The primary requisite in putting' down collectors 
is that they shall be so placed as not to be covered by mud, especially where the bottom is overlaid 
with ooze. In such cases they must be supported so as to prevent their falling into the mud, the 
effect of which would be to make them useless. In practice, I suspect, that it would be well to 
look after the collectors occasionally and to brush off the mud, because in some places I have 
noticed that thick deposits of sediment soon collect upon the upper surfaces. This accounts for 
the fact that several observers have noticed that the spat is disposed to attach itself and survive 
on the lower surface of the collectors. 

I am informed by Mr. C. P. Hull that the practice of strewing oyster-shells as spat-collectors 
on hard sea-bottom two or three fathoms deep is becoming quite common on the Connecticut 
shores of Long Island Sound. Here, the practice is to scatter two hundred and fifty to three 
hundred bushels of shells over an acre of bottom. The method there has also been so successful 
and profitable as a means of increasing the area of the oyster fishery that the price of the dead 
shells has increased and is likely to continue to do so, since the demand is greater than the supply. 
Mr. Hull, himself a practical oyster-culturist, proposes to introduce this system into practice on 
his projected plantations on the Chesapeake, where a beginning has already been made by this 
method under the direction of Captain Hine, at Cherrystone, the superintendent of the firm of 
Maltby & Co., of Norfolk, now largely interested as planters in the Cherrystone River. This 
method is the same as that extensively practiced in Europe. 

How an oyster takes on FLESH. — Among oystermen the business of fattening or feeding 
the Oyster is one of the most important, from the fact that upon the condition of the market 
able product largely depends its value. Fatness, so called, in the Oyster is a condition wholly 
different in nature from the state known under that name in stall-fed domestic animals. The 
turgidity of the reproductive organs is not usually indicative of fatness, as it appears some authors 
have supposed, Mobius being the only one who has apprehended its true nature. The word •• fat," 
as applied to indicate the condition of I lie Oyster when in flesh, is a misnomer, since it is not tat 
at all which is the immediate cause of the condition of plumpness which betokens a titness for 
market, but a very extensive deposit of protoplasmic matter which has been assimilated and laid 
down mainly in the substance of the mantle. It is this relatively large amount of delicate, easily 
digested protoplasm, stored up in the palps and mantle, which renders the Oyster so wholesome 
and nutritious. 

The deposition of this protoplasmic material in the mantle, palps, and body stands in intimate 
relation to the activity of the reproductive organs. During the spawning season Oysters are said 
to be "poor," that is to say poor in condition, for at this time the mantle, especially where it lies 

next .lie bodj aeh side, is \ ei \ thin and quite transparent ; the radiating pallial muscles along 

the border of the mantle, as well as its vessels and nerves, may now he readily studied under the 
microscope, owing to its transparency and the absence of opaque granular protoplasm. If we 
examine the reproductive organs at this time, as a rule, we will find them greatly developed and 
pouring out their products through two large ducts, the combined caliber of which is not far short 
of that of the intestine. It will be evident to any thinking mind that if the major part of the food 
material elaborated bj the digestive and nutritive systems goes to the ovaries or testes to be 
transformed into sex products, which are continually thrown off during the breeding season, little 
of such material can he stored up in the tissues of the body. We have described exactly what 
happens. In the month of September, when the Oysters in this latitude are for the mosl part 
done spawning, the drain of elaborated material having ceased to How from the openings of the 



FATTENING OP OYSTERS. 755 

reproductive organs, it is diverted in another direction, but is retained in the system and has to be 
deposited somewhere in the body. The most extensive deposits of this elaborated living matter 
occur in the mantle, body, and palps, the color of which rapidly changes from the watery, trans 
parent condition prevalent during the spawning season to a creainj white. The whole animal also 
acquires a solidity which it did not possess before; it loses its watery, impoverished appearance, 
together with its disposition to shrink to a fraction of its original bulk from an extensive toss of 
fluids when opened. The mantle and palps become opaque and thicker than before, and their 
substance is softer and more easily lacerated. The change here described undoubted!} affects the 
connective tissue principally, as elsewhere stated. The material of the latter has the milky 
appearance of the reproductive organ when mutilated, and may readily lie mistaken for the latter 
by the inexperienced. It appears that the generative and nutritive functions are opposed to each 
other in the Oyster as in other animals ; all of which indicates, too, the amount of energy which 
must be expended during the breeding season in the production of germs. Whatever surplus 
nutriment is stored up in the winter appears to be immediately devoted to the formation of germs 
upon the arrival of the warm months, when food is also probably most plentiful and when tin 
external conditions are right for the development of the embryos. The effort which the Oyster 
makes, at the expense of so much material, to reproduce its kind ought to be respected. In t lie 
protection of the Oyster during the close season we are simply following the dictates of experience 
and common sense. 

The account which we have given above of the physiology and interdependence of the 
fattening and reproductive processes of the Oyster, it seems to me, affords an opportunity to 
point out how little philosophy there is in the doctrine that Oysters may be fattened by putting 
them for a day or two in water less salt than that from which they were first taken, in order that 
they may be water-swollen by the action of osmose, so as to give to them a plump appearance. 
It is surprising how little dependence is to be placed upon the statements of oystermen and 
fishermen in regard to the habits of the objects with which they are supposed to be most familiar. 
And this statement, like many others of a similar kind, has no basis of fact and experimental 
evidence to rest upon. I may sum up the utter absurdity of the widespread belief in the possi- 
bility of fattening Oysters by removing them from salt to less salt water for a few days, by 
saying that it amounts to the same thing as to assert that water is a fatty or oleaginous substance ! 

The results of my most recent investigations upon the minute anatomy of Ostrea virginica may 
be fitly described in this place, since they have an important bearing upon the process of fattening. 
The subject of this investigation was one of the most impoverished-looking Oysters which it has 
ever been my fortune to find. It was collected on the 20th of July this present year (1882) and 
placed in a chromic acid solution of one per cent, for forty-eight hours, when it was washed and 
finally transferred to alcohol, to be cut into sections when convenient. This I have recently done. 
When the specimen in question was fresh it was characterized by the almost perfect transpar- 
ency of the mantle, and, as it afterwards turned out, the total atrophy of the generative organ. 
Before the hardening process had been undergone, the mantle was greatly distended by watery 
fluid, so much so that, after hardening, it had shrunken to about one-tenth of its bulk while in 
the fresh and living state. The hardened specimen was cut into thin sections after imbedding in 
paraffine, by means of a modification of the Taylor freezing microtome; the sections for thinness 
left nothing to be desired, and revealed a condition of things different from any previously 
observed by the writer in sections of either native or foreign Oysters. A careful microscopic 
scrutiny showed that nowhere in the section was there a trace of even a rudiment of the genera- 
tive network described as the atrophied condition in a previous portion of this paper. Not even 



756 NATURAL HISTORY OF AQUATIC ANIMALS. 

a trace of the connective tissue in which the rudiments of the latter are usually imbedded 
remained, but the hepatic follicles or ultimate saccules of the liver were lying in immediate 
contact with the mantle, with no tissue whatever intervening. 1 have hitherto found the liver 
surrounded by a thick stratum of connective tissue iu all of the specimens examined. The state- 
ments in a previous portion of this essay in regard to the existence of vessels which traverse this 
connective tissue mass will therefore have to be modified so far as to say that not only does the 
connective tissue of the body mass completely disappear, but also the vessels themselves which 
are excavated through its substance. 

Turning now to the condition of the mantle, I find this in a no less remarkable state than the 
parts already described. The " vesicular connective tissue cells," as they have appeared to me 
hitherto, have given place to an entirely different structure, apparently much less solid and 
substantial. Instead of the clearly defined coarsely cellular structure usually noticed in sections 
made, from less impoverished individuals, the tissue has now become very coarsely areolar, all trace 
of the peculiar nuclear bodies having vanished, together with the internal protoplasmic network 
which they so clearly exhibit. The areolae inclosed by the fibers of the connective tissue of the 
mantle are very coarse and may measure as much as half a millimeter across in sections of the 
hardened and shrunken specimen. When the mantle was gorged in life, with blood probably, some 
id.ea of the coarseness of these meshes may be formed. The meshes may then have measured lour 
or five millimeters in diameter, the resulting cavernous state of this highly elastic tissue enabling 
the mantle to become gorged or swollen by endosmosis to a remarkable degree, so much so as to 
cause the animal to be apparently bulky, yet in reality distended with sanious fluids merely. The 
question now arises. What has become of this connective tissue which has so completely disap- 
peared .' The only interpretation which I can offer is that the connective tissue substance has 
been transformed into sexual products which have been poured out by way of the efferent sexual 

ducts, and that our specimen represents the extrei if exhaustion consequent upon the completed 

exercise of the reproductive timet ion for t he season. The animal, in other words, has now exhausted 
its germ-producing resources, and must begin to teed ami store up material for the next season's 
generative products. It therefore becomes highly probable that the reproductive organs develop 
anew each season. M\ reason for thinking so is, that in this specimeu the atrophy or wasting 
away of the reproductive organ has gone so Ear thai no trace even of the efferent ducts of that body 
remains. The specimen, taken as it was in .Inly, also shows that the spawning season may be 
completed before the end of summer-. 

The connective tissue of the Oyster is. therefore, in reality transformed into ova and sperma- 
tozoa, depending simply upon the sex of the individual whether it shall be the former or the latter. 
This also raises the question whether the same individual may not be of a different sex during 
different seasons, since it appears that tin' whole reproductive organ disappears and develops ane\* 
every year. This it is however to be noted is arguing from a very different basis from that of 
some foreign writers who have been absurdly illogical enough to say that the Oyster was of a 
different sex in different years, apparently forget tin;; that it would be impossible to open the same 
individual twice in succession; since opening it kills the animal and puts the second examination 
totally out of the question. 

The function of the mesenchymal or connective tissue in the Oyster is, therefore, of the nature 
of a store of reserved material — protoplasm laid up for the purpose of conversion into germs as the 
reproductive organ develops anew. It is then in the highest degree improbable that it is of the 
nature of an oily or tatty substance, out of which it would lie impossible to form such highly vitalized 
bodies as the ova anil spermatozoa of the Oyster. While it is true that we find the mesenchyme 



RESEARCH TJPOX THE FATTENING OF OYSTERS. 757 

developed to the greatest extent during the winter when it may be said the Oyster is in the 
best condition as regards flesh, it does uot follow that this plumpness is due to fattj matters, but 
rather to a larger amount of protoplasm filling up the mantle, palps, and bodj mass. 

Our sections of the specimen described above show some other singular features which cannot 
be passed over in silence. The principal of these is the presence of thick-walled vessels in the 
ventral lobes of the mantle. In life we find branching vessels visible in the transparent mantle in 
very impoverished specimens, such as the one under discussion. These vessels unaj be followed I" 
what are apparently their ultimate ramifications and seem to end abruptly. It is these vessels 
which become obscured when the animal acquires flesh; they are. in fact, hidden in the thiols 
deposit of connective tissue laid down in the mantle. They are grayish or whitish in color as they 
shimmer through the transparent external epithelial and connective tissue layers of the mantle 
organ. They are also different in character from other vessels excavated in the connective tissue 
of the mantle, and which disappear with the atrophy of the hitter's substance, just as we noticed 
was the case with the vessels of the body mass. lu a specimen as greatly impoverished as the one 
under discussion, the thick-walled pallial vessels become very conspicuous in transverse sections. 
They may not have the same function as the bloodvessels of the ordinary wall-less form found in 
the connective tissue, from which type they may be at once distinguished by their thick, finely 
cellular walls. 

The almost total atrophy of the mesenchyme or mesoblast during the spawning season is a 
very remarkable fact, no less so than its regeneration. It appears, however, as far as I have been 
able to learn from transverse sections of very small spat, one-eighth to one-sixteenth of an inch 
in diameter, that the absence of a well-developed connective tissue deposit also characterizes the 
soft parts of the young animal. Indeed, the liver follicles here are relatively few in number, 
whereas they are very numerous in the adult. The follicles in the young also lie in immediate 
contact with the mantle, resembling in this respect the spawn-spent adults. This, for embryolo- 
gical reasons, ought to be so. We find, in fact, according to the unanimous testimony of observers, 
that the mesoblast in the Oyster develops by the proliferation of cells from the outer and inner 
layers into the segmentation or body 7 cavity. Why, then, should it not be absorbed and regener- 
ated in the same way in the adult 1 There seems to be no valid reason assignable why this should 
not be so, if we look upon the mesenchyme with its vessels and areolar tissue and cavernous 
spaces as having been primarily derived from the embryonic body cavity. 

The arrangement of the intestine as shown in sections of spat as small as that described 
above is essentially the same as in the adult. The second bend of the intestine crosses the 
gullet in the same way, but the double lateral longitudinal fold or induplication is not so well 
marked as in the intestine of the adult. The stomach is more nearly cybndrical and not so 
irregular as in the adult. The contents of both the stomach and intestine show that diatoms 
have formed a large proportion of the food of the young animal, in the sections of which, these 
contents, in a number of my preparations, have been kept in situ. 

The sections of the soft parts may be very readily double stained so as to bring out the 
tissues of the reproductive organs very distinctly. To effect this, I throw the section into a 
solution of methyl green for a few minutes, then into magenta, when it will be found that 
the green will dye only the reproductive tissues, leaving the others scarcely tinged, while the red 
will stain the mantle, liver, and connective tissues, mapping out these parts so distinctly as to 
make a really useful as well as beautiful preparation. 

Considerable care must be exercised in the preparation of the color solutions, so as not to 
have them too intense. The sections should also be at once and quickly dehydrated or else the 



758 NATURAL HISTORY OF AQUATIC ANIMALS. 

alcohol will abstract the green and spoil in part the effect of the double .stain. In making 
sections, the best ones which I have ever made have been prepared from portions of whole 
Oysters which had been imbedded in paraffine. the latter substance having in the molten state 
interpenetrated all the cavities and spaces in the hardened specimen, which had been previously 
dehydrated and saturated with oil of turpentine. 

Note on tlir organ of Bojanus of the Ogster. — In the first part of this paper it is stated that the organ of Bojanus is 
rudimentary or wanting in the Oyster. This statement must now be modified. Within the past year, M. Hoek, of 
Leyden, has demonstrated the existence of the organ of Bojanus in Ostrea edulis, and the writer has shown it to be present 
in the American species as a crescent-shaped glandular or canal itulated structure lying just below the adductor and close 
against it, as a paired organ which also extends slightly into the substance of the mantle on either side. M. Hoek has 
shown that, as in other acephalous niollusks, this organ communicates with the pericardiac cavity and the genital 
openings. Its function is excretory. 

Valves (if lite haul. — A pair of very distinct valvular folds separates each of the auricles of the heart of the Oyster 
from the ventricle, opening upward into the latter. They prevent the blood from regurgitating into the auricles, and 
cause the blood-current to assume one constant direction, viz, from the auricles to the ventricles, and from the latter 
through the anterior and posterior aortic vessels to the various parts of the body. 

Fixation of the sjmt. — Recent studies have led me to the conclusion that the existence of a byssus in the fry of the 
Oyster is very doubtful, and that fixation is accomplished at a very early stage, possibly twenty-four hours after the 
embryos commence to swim, by the border of the mantle, as I have endeavored to show in my paper "On the Fixation of 
the Fry of the Oyster," illustrated with figures, and recently prepared for the Bulletin of the United States Fish Com- 
mission, where I also show that the beaks of the larval valves aie constantly directed one way. and that the hinge end 
of the larval shell is inclined upward, the free margin of the left larval valve being brought into close contact with the 
surface to which attachment occurs through the instrumentality of the margin of the mantle. The attachment, itself is a 
very firm one, and consists of the horny matrix of the calcareous material which serves as a cement to glue the free 
margin of the lower valve of the fry and spat to the surface which has been chosen as a permanent abode. 



PLATE 253. 




THE COMMON SQUID. 

Loligo Pealei (Le S.). 




Drawing by Prof. A. E. Vor 



THE GIANT SQUID. 

Architeuthis princeps, Verrill. 
rom specimen obtained :it Fortune Bay, Newfoundland, December, 1874. 






THE SHORT-FINNED SQUID. 

Ommastrephes illecebrosus (Le S.), Verrill. 
Drawing of youBg male froiu Provincetown, Mass. 



PLATE 254. 




SEA SNAILS, PERIWINKLES, DRILLS, AND BORERS. 



Fig. 1. Lunatia lieros, p. 700. 

Fig. 2. Purpura lapillus, p. 698. 

Fig. 3. Purpura lapillus, banded variety. 

Fig. 4. Xererifa duplicate, p. 700. 

Fig. 5. Ilyanasaa obsohta, p. 696. 

Fig. 6. Trilia triviltata. 



Fig. 7. The Whelk, Succinum undatum, p. 699. 

Fig. 8. The Periwinkle, FuJijur atrial, p. 694. 

Fig. 9. Astyris zonalis. 

Fig. 10. AstyrisVunata. 

Fig. 11. Bissoa aculeun. 

Fig. 12. The Drill or Borer, Urosalpinx ciuerea, p. 697. 



PLATE 255. 







Fig. 1. Angulus tener. 

See Eeport TJ. S. Fish Commission. Part I, p. 077. 
Animal reduced one-half. 
Fig. 2. The long clam, soft clam, or Nanninose, Mya 
arena/Ha. 
"With animal in extension, reduced to one-half the nat- 
ural size. 
Fig. 3. Tagelus qibbus. . 

See Eeport TJ. S. Fish Commission. Part I. p. «/■>. with 
animal. The siphon not fully extended. One-halt 
natural size. 
Fig. 4. The Razor Clam, Ensatella americana, p. 707. 
"With animal extended. One-half natural size. 




Fig. 5. Tbe Razor Clam with some of the terminal 

papillae enlarged. 
Fig. 6. The Razor Clam, Ensatella americana. 

Shell natural size. 
Fig. 7. The Ship Worm, Teredo iiin-ali.f. 

Enlarged two diameters. 
Fig. 8. The Scallop, Pecten irradians. p. 709. 

Natural size. 
Fig. 9. The Bloody Clam, Argina pexata. 



PLATE 256. 




Fig. 3. 



Fig. 1. The Quahaug or Little-uecked Clam, Venus viereenaria. 

Natural size. 
Fig. 2, The Quahaug of Puget Sound, Saxidomus nuttalli. 

Natural size of large specimen. Drawn by J. H. Emerton. 



Fig. 3. The Gaper Clam of the West Coast, Sckizotk ccrus nut- 
talli (Conrad). 
(I.) Specimen of ordinary si/A*, reduced about one-fourth in length. 
The siplions an- somewhat eontiaeted ; (lit- font (F) expands 
about as usual. 
(II.) Outline of the left valve of a larger specimen, reduced to the 
same extent. Drawn from nature by U. E. C. Steams. 



PLATE 257. 




PLATE 257. 




THE GEODUCK, OR GIANT CLAM OF THE PACIFIC. 



Glycimeris gene 



nlil win i, i.liv. Ill iii.nii. K lliiiwii l.y IS. E. ('. sir; 



PLATE 258. 





Fig. 6. 



MUSSELS AND SEA CLAMS. 



Fig. 1. The Beach Clam or lien Clam, Spisula soli- 

disslma, p. 708. Natural size. 
Fig. 2. The Sea Clam, Ci/prina islandica. Natural 



]'ig. :;. The Mussel, Mytiliis edidis, p. 709. 
Fig. 1 The Black Horse .Mussel. Modiola nigra. 
Fig. .". The Rough Mussel, Modiola plicatnla, p. 709. 
Fig. (i. The Horse Mussel, Modiola modiolus, p. 709. 



PLATE 259. 
Explanation of Fig. 1. 

A. Hinge or anterior nmhonal end of the left valve of an adult oyster, upon which the soft parts of the animal are represented as they lie 

in situ, but with the greater pai*t of the mantle of the right side removed. 
a/u. The auricle of the right side of the heart contracted. 

B. Posterior or ventral end of the left valve, which in lite is usually directed upward more or less, and during the act of feeding and respira 

tion is separated slightly from the margin of its fellow of the opposite side to admit tin- water needful for respiration, and which 

also contains the animal's food in suspension. 
Mm. Body-mass, traversed superficially by the generative ducts ge. 
t'j. The organ of Bojanus, or "renal" organ, of the right aide of the oyster. (The ducts which it sends into the mantle are not shown, nor 

is its connection with tin- genito-urinary sinus 8 indicated.) 
f>l>. The large branchial pores which open from the subdivided cavities of Ihe pouch-like gills g into the cloaca cl. 
hr. Theanterior branch iooardiac " vein, ' which conveys part of the blood from the gills to the auricle. 
c. Right pericardiac membrane, which has been thrown hack over M in order to expose the hear! >;■ and an. 
cl. Cloacal space, through which the water used in respiration passes out, and into which the excrement of the animal is discharged from the 

Villi v. 

<i. Nervous commissure of the right side, which connects the parieto-splanchnic with the supra-cesophageal ganglion. 

y. <.;ills, which extend as tour flattened transversely subdivided sacs from the palps p to the point y. at the edge of the mantle. 

ge. Superficial network of the generative duets as they appear when the oyster i.-- spawning. 

h Groove in the hinge end of the left valve, which receives the ridge de\ eloped in the corresponding situation on the right one. 

;. Dark brown clast ic body or ligament by which the valves arc held together at the hinge. 

M. Great adductor muscle, which is here viewed from the end, and which is attached to the inner faces of the valves over the dark purple 

scars. It opposes the elastic ligament and closes the valves, and corresponds to the posterior adductor muscle of dim vary mollusks. 
m. Mouth. 

„,r Mantle of the left side fringed with two rows of tentacles. 
ml'. Portion of the mantle of the right side. 
n to z marks tin- extent to which the right and left leaves of the mantle are joined together; the hood thus formed above and at the sides of 

the palps is called the cUCullllS. 

P. Palps exposed, a part of the cucullus on the right being cut away 

pd. Pedal muscle of right side, which is also inserted upon the shell of the same side. 

pg. ParietO splanchnic ganglion. 

s. Genital opening of the right side. 

sg, Supra-cesophagea] ganglion. 

v. Vent or anus. 

ve. Ventricle of the heart, whioh is dilated, or in the condition of diastole. 

.r.rr. Areas at the edge of the inner surface of the shell, where intruded mud has been inclosed by a thin lamina of shelly matter deposited 

by i tic mantle. 
y. Point at the posterior extremity of the gills, where the right and left leaves of the mantle are joined together by the membrane which 

supports the gills. 

Explanation of Fig. 2. 

This figure was drawn from a dissection of a hardened siieeimen which had been removed from the shell, and is viewed from the loft 
side, the superficial tissues of the left half of the body-mass having been remoi ed in order to display the .surface of the "liver" L, with its 
large clusters of minute follicles, and part of the course of the inte- 1 ine i. At i the « idened pyloric part of the intestine is shown, which 
incloses tin crystalline style. Tin* ventricle ve and auricle are mm h contracted, and a spacious pericardiac space is shown on either sideof it. 

ge. Stratum of reproductive follicles. The remaining letters of reference are the same as in Fig. 1. 

Explanation of Fig. 3. 

This figure of the viscera of the oyster Is also drawn in part from the hardened soft parts, but is viewed from the right side. The £Tea ( 
ducts^ of the "liver" L are shown cut open longitudinally, and are represented as opening directly into the cavity of the stomach tt, in front 
of which the oesophagus »c is also shown running back from the mouth m. This figure shows almost the entire intestine, with its w ,l, n. ■,] 
anterior end,/, and its course and curvature as here represented is what will be found constant, even when hundreds of specimens are 
examined. Nearly all the substance of the body-mass has been carefully removed from the right half of the body; and where the edges of the 
body have been nit through, the stratum of reproductive tissue </*> is also shown. The corrugated outer surface of the inner or lower palp 
at P. The remaining letters have the same significance as in the previous figures. 

Explanation of Fig. 4. 

This represents a section or Blice cut from the soft parts of an oyster at the h\ t ] of the doited line o In Fig. 3, and viewed from its ante- 
rior surface. The tissues and structures, which have been cut across in this section, are as follow a 
a'. The dorsal or posterior branch of the great splanchnic artery. 
a". The anterior or ventral branch of the splanchnic artery. 
hr. Branchial vessels. 
c. The connective tissue which envelops the organs contained in the body-mass and forms the principal portion of the substance of the 

animal in winter. 
g. The L,ills cut across, showing their hollow interiors. 
ge. Stratum of reproductive follicles, which immediately underlies the mantle layer mt. Intestinal canal cut through at two points. <>. pos 

teriorh and ant. Hurl \. sin. win- the manner in which the intestinal walls are folded inwards upon themselves. 

LL. Right and h fi lobes of the liver, embedded in the connective tissue and most considerably developed at the sides and below the stomach, 

tb. Suprab ranch ial space. 

st. Stomach, showing its irregular form ami connection by means of spacious ducte with the "live] 

uc. Vena cava. 




PLATE 259. 






For explanation of figure 



;e« opposite page. 



LIBRARY OF CONGRESS 



002 896 666 



